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AC8ICUITUPF 


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UNIVERSITY  OF  ILLINOIS, 

Agricultural  Experiment  Station 

CHAMPAIGN,  FEBRUARY,  189J. 


BULLETIN  NO.  24. 


VARIATIONS  IN  MILK. 

This  bulletin  gives  some  results  obtained  from  observations  made 
with  six  cows  during  one  period  of  lactation. 

SUMMARY. 

The  butter  fat  was  the  most  changeable  constituent  of  the  milk. 
The  per  cent  of  solids  not  fat  was  quite  uniform.  Both  were  higher  in 
the  last  part  of  the  period  of  lactation  than  in  the  first  when  the  cows 
were  fresh  and  the  maximum  quantity  of  milk  was  produced.  This  was 
especially  true  of  the  fat.  As  the  activity  of  the  milk  glands  gradually 
declines  until  the  flow  of  milk  ceases,  the  formation  of  the  fat  seems  to 
hold  out  better  than  the  other  constituents  of  the  milk. 

Calculations  of  the  total  amount  of  milk  and  of  butter  fat  were 
made  from  one,  two,  three,  and  four  of  the  weights  and  tests  of  each 
month.  The  results  so  obtained  were  found  to  be  in  many  cases  99,  and 
in  no  case  less  than  90  per  cent  of  the  totals  found  by  the  daily  weights 
and  tests. 

A  gradual  increase  of  the  grain  feed  from  12  to  24  Ib.  a  day  per 
head  and  the  change  from  stable  to  pasture  feed  each  increased  the 
yield  of  milk,  but  had  very  little  if  any  effect  on  its  quality. 

OBJECT. 

The  object  of  this  work  was  to  get  an  exact  record  of  the  perform- 
ance of  different  cows:  To  note  what  influence,  if  any,  the  changes  in 
weather,  season  and  feed  actually  had  on  these  cows;  their  variation  in 
live  weight  and  in  quantity  of  milk;  the  chemical  composition  of  the 
milk  in  different  parts  of  the  period  of  lactation;  how  the  composition 
was  changed  by  any  accidental  or  normal  occurrence  during  the  every 
day  life  of  a  cow  for  one  year;  the  relative  sensitiveness  of  different 
cows  to  the  same  cause  or  influence;  to  what  extent  the  richness  of  milk 
was  changed  by  a  very  large  quantity  of  concentrated  feed ;  and  whether 
any  or  all  the  variations  which  might  be  noticed  in  the  quantity  and 
quality  of  the  milk,  applied  to  each  of  the  cows  included  in  this  trial. 


38 


BULLETIN    NO.    24. 


^February, 


CONDITIONS  AND  METHODS. 

The  experiment  began  July  6,  1891,  and  ended  Oct.  14,  1892. 
Some  experience  in  this  line  of  work  was  obtained  with  other  cows  dur- 
ing the  preceding  months  of  May  and  June. 

The  shortest  milking  period  of  any  of  the  cows  was  278,  the  long- 
est 428,  days. 

An  analysis  of  the  weighed  milk  of  each  cow  was  made  nearly 
every  day.  This  included  an  estimation  of  the  per  cent  of  solids  and  of 
butter  fat  in  the  daily  milk,  and  of  casein  and  fat  in  a  week's  composite 
sample. 

None  of  the  six  cows  was  a  superior  representative  of  its  breed. 
They  were  average  animals,  such  as  are  the  actual  producers  of  the 
greater  part  of  the  country's  milk  supply. 


BREED  AND  AGE  OF  THE  Cows. 


No. 

Name. 

Breed. 

Average 
weight. 

Age,  years, 
July,  1891. 

Date  of 
last  calf. 

No.  of  days 
milk  was  tested 

i 

4 
5 

Jersey  
Jock  
Med  

Jersey  
Holstein  .... 
Holstein  .... 

859 
1361 
1054 

3 

8 
8 

Sept  
Jan  
Nov  

307 
278 
322 

3 
16 
18 

Grace   
Duchess  .  . 
Duchess  .  . 

Shorthorn.  .  . 
Shorthorn.  .  . 
Shorthorn.  .  . 

1022 

1108 
1174 

8 
7 

June  
August.  .  . 
August 

428 
332 
342 

The  milking  was  done  between  the  hours  of  five  and  six  both  night 
and  morning.  Each  cow  was  not  milked  at  exactly  the  same  hour  and 
minute  every  day,  but  the  milking  time  was  subject  to  such  interrup- 
tions as  are  common  in  farm  practice;  hence  there  was  observed  no  uni- 
form difference  in  amount  or  richness  between  the  night  and  morning 
milk  ef  the  cow  whose  milk  of  each  milking  was  tested. 

The  cows  were  always  tied  up  in  the  stable  when  milked.  From 
May  ist  to  Nov.  ist  they  were  either  in  the  yard  or  pasture  both  day 
and  night  except  at  milking  time.  Beginning  Nov.  ist  the  cows  were 
stabled  and  only  turned  out  into  the  yard  a  part  of  each  day.  This  con- 
tinued through  the  winter  and  spring  until  May  ist  when  pasture  feed- 
ing began. 

The  weighing  and  testing  of  each  cow's  milk  began  about  two 
weeks  after  calving. 

A  record  was  made  of  the  pounds  of  milk  given  by  each  cow  at 
each  milking.  The  milk  of  cow  No.  i  was  sampled  and  tested  after 
each  milking. 

A  mixture  of  the  morning  and  night  milk  of  each  of  the  other  cows 
was  tested  every  day.  This  gave  a  daily  test  of  the  milk  from  each  of 
five  cows,  and  of  one  cow's  milk  two  tests  each  day. 

The  number  of  days  in  the  year  when  the  analyses  of  the  different 
cows'  milk  were  lost,  is  shown  in  the  following  table. 


'893-] 


VARIATIONS    IN    MILK. 


39 


OMITTED  ANALYSES. 


Cow. 

Number  of  determinations  not  made. 

Of  solids. 

Of  fat 

Of  soiids  not  fat. 

No.  3 

16 

6 

16 

No.  4 

7 

3 

8 

No.  5 

9 

4 

10 

No.  16 

ir 

2 

ii 

No.  18 

1.4 

6 

15 

No    iia"  m' 

6 

3 

6 

i>0'      )  p.  m. 

15 

4 

16 

These  missing  tests  were  scattered  throughout  the  year  and  were 
caused  by  some  accident. 

The  cows  were  weighed  every  Monday  at  about  10  a.  m. 

The  milking,  weighing  of  the  milk,  and  taking  the  samples  for  an- 
alysis were  nearly  all  done  by  one  man.  He  had  some  assistance  at 
different  times  in  the  year. 

The  history  of  the  cows'  care  and  feed  throughout  the  year  was 
obtained  from  Mr.  F.  D.  Gardner,  assistant  agriculturist  of  the  Station. 

The  writer  is  responsible  only  for  suggesting  that  an  accurate  record 
be  kept,  and,  while  the  cows  were  stable-fed  in  the  winter,  that  the  grain 
should  be  gradually  increased  till  the  cows'  daily  ration  was  unusually 
large.  From  the  figures  thus  obtained,  the  inferences  in  regard  to  the 
effect  of  the  grain  on  the  quantity  and  quality  of  the  milk  have  been 
deduced  as  herein  described. 

All  the  samples  of  milk  were  brought  to  the  laboratory  and  tested 
daily.  Nearly  all  the  analyses  were  made  by  Mr.  Nelson,  assistant 
chemist  of  the  Station.  This  work  amounted  to  something  over  4,550 
separate  tests  and  analyses. 

All  the  calculations  necessary  in  making  the  tabular  and  other  rec- 
ords contained  in  this  bulletin  have  been  made  by  two  computers,  in 
order  to  insure  accuracy  in  the  figures. 

The  tests  made  of  each  sample  of  milk  included  the  per  cent  of  butter 
fat,  total  solids,  and  solids  not  fat.  The  latter  was  calculated  by  difference. 

A  composite  sample  was  collected  from  the  milk  of  each  cow.  The 
per  cent  of  casein  and  of  butter  fat  was  determined  in  each  of  these  com- 
posite samples  once  a  week,  or  after  there  was  accumulated  in  them  a 
mixture  of  samples  taken  from  every  milking  for  seven  days.  No  pre- 
servative was  added  to  these  composite  samples  ;  but  powdered  lye  was 
used  to  thin  the  sour  milk  when  it  was  tested.  This  operation  was  per- 
formed as  described  by  the  writer  in  bulletin  No.  16,  p.  510,  of  this 
Station. 

TESTS  OF  THE  COMPOSITE  SAMPLES  DURING  THE  YEAR. 
The  butter  fat  tests  of  the  composite  samples  wrere  com- 
pared with  the  average  of  the  tests  made  of  the  milk  each 
day  during  the  time  the  composite  samples  were  collected. 
This  comparison  was  made  with  the  milk  of  each  cow  every  week 
during  the  entire  year.  This  work  gave  an  opportunity  to  re- 


140  BULLETIN    NO.    24.  [February  ^ 

cord  observations  on  the  use  of  the  method  in  all  seasons  of  the  year, 
and  with  the  milk  of  different  breeds  of  cows.  It  also  gave  experience 
in  the  manipulation.  We  have  not  found  it  necessary  to  change  materi- 
ally the  method  as  originally  described.  It  can  be  and  is  successfully 
used  by  creameries  in  paying  patrons  on  the  "  test  plan,"  and  our  year's 
experience  has  taught  us  that  with  a  fair  amount  of  care  it  is  practically 
accurate. 

An  agreement  of  the  test  of  the  composite  sample  with  the  average 
test  was  most  difficult  to  obtain  with  very  rich  milk.  With  such  milk, 
the  composite  sample  test  was  often  low.  Milk  of  average  compo- 
sition (3.5  par  cent  fat)  gave  almost  uniformly  close  agreement. 

METHODS  USED  FOR  ANALYZING  THE  MILK. 

All  the  samples  of  milk  were  tested  for  butter  fat  by  Dr.  Babcock's 
method.  The  centrifugal  machine  used  for  making  the  separation  of  fat 
from  the  acid  mixture  was  run  by  a  one-horse  power  electric  motor. 
[This  is  connected  with  the  street  electric  railway  of  the  city  and  makes 
a  very  convenient  and  useful  laboratory  power  for  grinding  samples  of 
feed.  The  speed  is  sufficiently  uniform  for  testing  milk.]  During  the 
first  few  months  each  sample  of  milk  was  tested  for  butter  fat  in  dupli- 
cate ;  later  on  the  accuracy  of  each  day's  work  was  tested  in  the  follow- 
ing way  :  A  mixture  was  made  of  equal  quantities  of  milk  from  all 
the  samples  tested  at  one  time.  A  test  of  this  mixed  milk  was  compared 
with  an  average  of  the  separate  tests  of  the  several  samples  used  in  mak- 
ing the  mixture.  If  the  two  results  agreed  within  one-tenth  of  one  per 
cent,  the  work  was  not  repeated.  An  examination  was  made  of  the  cor- 
rectness of  the  calibrations  on  each  new  test  bottle  used. 

The  per  cent  of  total  solids  in  each  sample  of  milk  was  determined 
by  drying  in  an  oven  surrounded  by  boiling  water  five  grams  of  milk 
with  about  25  grams  of  clean  sea  sand. 

FEED  OF  THE  Cows  DURING  THE  YEAR. 

The   cows    were    at    pasture    from    May    ist    to    Nov.    ist.     The 
pasture  was   mostly  blue   grass   with   some  timothy   and   white  clover. 
The  severe  drought  in  the  summer  of    1891  made  the  feed  rather  short, 
and  from  July    28th  to  Oct.    ist  each  cow  was   given  15  Ib.  green  corn- 
fodder  at  milking  time,  or  30   Ib.  a  day.     Oct.  ist  to  26th   corn-fodder, 
with  the  largest  ears  picked  out,  was  thrown  into  the  pasture  and  10  Ib. 
broken   corn  with    5   Ib.  hay  was   fed    at   the    stable  daily.     Oct.    26th 
i  Ib.  oil    meal  was    added    to   this  ration.     Nov.    ist    the  pasture  feed- 
ing stopped   and   stable  feeding  began  with  a  daily  feed  per  head  of   20 
Ib.  broken    ear    corn,  10    Ib.  hay,  and    2    Ib.    oil  meal.     Nov.   nth    be- 
gan feeding  ensilage,   gradually  increasing  the  quantity  to   all  that  the 
cows  would  eat  and  decreasing  the  daily  feed  of  broken  corn.    This  was 
continued    with  2  Ib.  oil  meal  and  6    to    10    Ib.    hay    daily    until    Dec. 
25th.     The  Shorthorn  cows  ate  the  ensilage  with  a  relish;  the  one  Jersey 
was  more  dainty  at  first  but  gradually  developed  an  appetite  for  it. 


1893-]  VARIATIONS    IN    MILK.  j^! 

Dec.  25th  the  cows  were  divided  into  two  lots.  Lot  i  con- 
tained cows  No.  i,  3,  and  5;  lot  2  No.  4,  16,  and  18.  The  object  of  this 
separation  was  to  increase  gradually  the  grain  feed  of  lot  i,  and  .note  the 
effect  on  the  milk.  The  feed  of  lot  2  continued  unchanged  until  the 
supply  of  ensilage  was  exhausted,  Jan.  i,  1892.  Jan.  ist  to 
March  ist  the  daily  feed  per  cow  was  20  Ib.  broken  corn  (equal  to  16  Ib. 
shelled  corn),  and  12  Ib.  hay.  After  Feb.  i6th  No.  16  and  18 
were  fed  oat  straw  instead  of  hay.  March  ist  to  April  Sth  the  grain 
feed  was  changed  to  20  Ib.  daily  of  a  mixture  made  of  two  parts  corn 
and  cob  meal,  i  part  wheat  bran,  and  i  part  oil  meal.  April  Sth  to  i4th 
this  feed  was  decreased  by  taking  out  the  bran.  April  i4th  the  daily 
feed  was  changed  to  6  Ib.  oil  meal  and  22  Ib.  hay.  April  3oth  the  cows 
were  turned  out  to  a  good  pasture  and  no  other  feed  was  given.  The 
changes  in  the  daily  feed  per  head  of  the  cows  in  lot  i  after  Dec.  25th, 
are  given  on  page  162. 

The  records  of  the  daily  weights  and  tests  of  the  milk  of  each  cow 
are  not  given  here;  but  from  them  the  results  shown  in  the  following 
tables  have  been  calculated.  These  tables  give  the  live  weight  of  the 
cow  each  month.  This  is  an  average  of  the  weights  made  every  week. 
The  average  weight  of  milk  given  per  day  for  every  month,  and  the 
largest  and  smallest  amount  of  milk  produced  on  any  one  day  of  the 
month.  The  daily  average  per  month  and  extremes  in  per  cent  of 
solids,  butter  fat,  and  solids  not  fat  found  in  the  milk;  the  average  of  the 
per  cents  of  casein  found  in  the  four  composite  samples  of  milk  collected 
every  month  and  the  pounds  of  solids,  butter  fat,  and  solids  not  fat  cal- 
culated from  those  weights  and  analyses. 

The  summary  at  the  foot  of  each  table  shows  the  total  weight 
of  milk,  butter  fat,  and  solids  not  fat  produced  by  each  cow  during 
the  period  of  lactation,  and  the  average  per  day  for  the  whole  time. 
Also  the  extreme  variations  observed  on  any  day  during  the  experiment. 

The  daily  average  per  cents  of  solids  and  butter  fat  are  found  by 
dividing  the  total  weight  of  solids  and  of  fat  by  the  total  weight  of 
milk,  and  multiplying  by  TOO. 

The  length  of  the  period  of  lactation,  or  the  number  of  days 
the  cow  was  milked  during  the  year,  is  given  at  the  top  of  the  tables. 

Cow  No.  i — Jersey. — This  cow  was  milked  307.  days.  She 
was  nearly  4  years  old  when  this  record  began,  and  her  live  weight 
has  varied  during  this  test  from  745  to  962  Ib.  She  gave  5,043  Ib. 
milk,  which  contained  254  Ib.  butter  fat,  equal  to  305  Ib.  of  butter. 

WEIGHT    OF    MILK. 

The  most  milk  given  at  any  one  milking  was  14  Ib. ;  the  least, 
i  Ib.  The  most  milk  given  on  any  one  day  was  25.5  Ib.,  and  the 
average  per  day  for  the  whole  time  was  16.4  Ib. 

The  table  shows  that  at  some  one  milking  during  a  month  the 


I42 


BULLETIN    NO.    24. 


Cow   No.    i,    JERSEY.  —  THE    DAILY    AVERAGE    AND 
Weighing  and  Testing  the  milk  began  Oct.  6, 


Month. 

r 
<* 
a 

^ 

Pounds  of  milk. 

Per  cent  of  solids. 

Per 
p.m. 

p  m. 

a.m. 

Daily. 

p.m. 

a.m. 

Daily. 

> 
< 

W 

X 
n 

> 
< 

W 

X 

pf 

> 
< 

W 

X 

*T 

> 
< 

ft 

X 

n  . 

> 
< 

M 

X 

^ 

> 
< 

W 

X 
n 

> 
< 

W 

n 

Oct   6  to  31 

851 

797 
771 

769 
827 
856 
864 
890 
927 
947 
957 

10.6 
83 
7-5 
86 

8-7 
8.7 
8.1 
8.4 

6-4 
3-8 
i  4 

12 

8-5 

95 
6 

9 
3  5 

9-2 

7-5 
10.5 

7-5 
95 
7-2 

[0.2 
6.2 

9-7 
7 
7-2 
5 

5-7 

i 

2 

I 

12.3 
107 

9-5 
n.  i 
10  6 

8.8 
7-7 
7-6 
63 
42 
i  3 

J4 

10 
12 

9-5 
n-5 

8 

12  5 

IO 

11.7 

9-2 

9  5 

8 

10 
5-2 

t>  5 
6 

7-5 
5 
7 
i-5 

2 

22.  9 
19 

J7 

19.7 

19  3 

17.5 
15-8 
16 

12.8 

8 
2  7 

25-5 
185 

21 
I6.5 
20.5 
I2.5 

21-5 
17.7 

20  7 

17 

18.5 

15  7 

20.2 
II.4 

18 
13  5 

I4  2 
10.7 
12.2 
3 

4 

2 

14 
14 
138 
14.4 
14-3 
14-5 
14.8 

15 
!5-3 
16.8 
17-6 

14.8 
13 
15-5 
II.9 

16.2 

12  6 

18.6 

12.8 

19.2 

13  5 
16 

13  9 
16.6 
13.2 
17.1 
136 
16  8 
r4-3 

20.1 

13-7 
19.9 

16.1 

13-7 

13-8 

13-8 
14.4 
M-3 
H  7 
15.2 

15:3 

15.5 
16.7 

16.1 

M-7 
12.4 

15  5 
12.7 

15   2 

13 

2O.  2 
13-6 

166 
13  3 
15-5 
14.1 
16.7 
14.1 
16.9 
13-8 
16.9 
14.2 
22.4 
14.2 
17.7 
149 

13-8 
13-9 
13-8 
14.4 

M  3 
146 

r5 
i5-i 
i5-4 
16.8 
16.8 

I4.6 

I3-I 
14  9 

13 
15 
I3-I 
17-5 
'3-4 
16.7 
136 

15-4 
14.1 
16.6 

14 
16.7 

14 
16.3 
14-5 
19.4 
14-8 
183 
15.6 

4-8 
4-9 
4-9 
5 
4-7 
5 
5-4 
5-i 
5-6 
6-3 
7-3 

6 
4 
6-5 
2.9 

7-3 
3-3 
9-4 
39 

10.2 

4-i 

6.2 

4-5 
7-i 
4 
5-9 
4 
7-i 
46 
9-7 
33 
9-2 

6.2 

November  

December 

January  .  . 

February 

March  

April   . 

May 

June  

July   . 

Aug.  i  to  7  

For    the 


12 

I 

J4 

i 

16.4 

25.5 

20.1 

ii.  9 

|22.4| 
112.4114.4 

19.4 
13 

10.2 
2-9 

Total 

5o< 

\3-9 

quantity  of  milk  was  considerably  smaller  or  larger  than  usual;  but 
the  total  milk  of  the  different  months  was  quite  uniform.  This  cow 
was  milked  about  10  months,  and  during  9  months  of  this  time  her 
average  daily  milk  decreased  only  from  23  to  13  lb.,  then  in  the  last 
month  she  dried  up  very  fast.  This  characteristic  was  not  so  marked 
with  any  of  the  other  cows.  She  gave  more  milk  at  the  morning 
than  at  the  night  milking  for  the  first  six  months.  During  this  time 
the  morning  milk  was  i  to  4  lb.  more  than  the  night  milk.  There 
was  no  great  difference  either  way  in  the  amount  of  milk  given  at 
the  two  daily  milkings  in  the  last  4  months  of  her  record.  The 
night  milk  was  i  to  2  lb.  greater  during  the  first  week  the  cow 
was  at  pasture;  but  for  the  remainder  of  the  time  very  nearly  the 
same  quantity  was  given  at  both  milkings.  When  a  change  in  feed 
was  made  April  i5th  from  12  lb.  corn  and  cob  meal,  6  lb.  oil  meal, 
and  12  lb.  hay  to  6  lb.  oil  meal  and  22  lb.  hay,  there  was  a  sudden 
drop  of  4  lb.  in  the  amount  of  milk  given,  and  this  loss  of  milk 
continued  till  May  ist  when  pasture  feeding  began.  Then  the  milk 
increased  in  quantity  to  about  what  it  had  been  in  the  first  part  of 
Apri).  There  was  a  gradual  decrease  in  the  flow  of  milk  from  May 


•893-] 


VARIATIONS    IN    MILK. 


'43 


EXTREMES  OBSERVED  EACH  MONTH  FOR  EACH  MILKING. 
1891,  and  continued  to  August  7,  1892—307  days. 


cent  of  fat. 

Per  cent  of  solids  not  tat. 

Ker  eent  easein.  jSolids.lb 

Fat,  Ib. 

8.  not  F. 

a  m. 

Daily. 

p.m 

a.m 

Da 

> 
< 

ily. 

^ 
3 

*a 
3 

I 
^< 

Daily. 

Daily. 

Daily. 

> 
< 

W 

X 

^ 

> 
< 

M 

X 

*T 

> 
< 

W 

X 

^ 

> 
< 

W 

X 
"1 

W 
ft 

> 
< 

W 

x 

n" 

> 
< 

W 
x^ 

n 

> 
< 

W 

X 

^ 

4  3 

5-2 

3-4 

4-5 

r:  - 

9-8 
8.1 

94 

9.6 
89 

93 

9-8 
8.6 

3  32 

3-29 

3-3 

3-21 

3-64 
2.42 

1.05 

1.27 
•73 

2.16 

2  45 
1.69 

4-4 

6.1 
3-3 

4-6 

5-6 
4-i 

9-i 

96 
8.4 

9-4 

9-7 
8-5 

92 

9-5 
8-7 

3-13 

3-39 

326 

2-63 

3-03 

2.22 

.88 

1.07 
•73 

i  75 

1.96 
i-49 

4  5 

5-8 
3-8 

4-7 

59 
39 

8-9 

97 
8-4 

93 

10.6 
7-8 

9-i 

9-5 

87 

2.98 

3  10 

304 

2.36 

2.92 

1.72 

.8 

i 

•59 

1.56 

1-94 
I-  1.3 

4.8 

II.  2 

4 

4-9 

8  2 

42 

94 

9-7 

8.4 

9.6 

10  5 
9 

9-5 

10 
8.9 

3.38 

3  49 

3-43 

2.82 

348 
2.47 

•97 

i  3i 
.81 

1.85 

2 

i-55 

4-5 

68 
3-6 

46 

74 

4 

9-6 

9-9 
9 

9.8 

10.3 

9-4 

97 

IO 

9-3 

3.68 

3-68 

3.68 

2-75 

3.22 
2.4 

.88 

i-4 
.76 

1.87 

2.1 

1.6 

4.8 

5-8 
44 

4  9 

5-5 
4.6 

9-5 

9-8 
9-2 

99 

10.4 
9-5 

97 

10 

93 

369 

3  70 

3-69 

2-57 

2-94 
2-4 

.86 

.98 
.81 

1.71 

2.06 

i-53 

5-4 

6.9 
4-5 

5-4 

7 
4-4 

9-4 

10  2 
7.6 

9-8 

10  2 

94 

9-6 

10.  1 
Q.I 

3  54 

3  5' 

3-52 

236 

2.87 

1.86 

.84 

1.04 
•7 

1.52 

19 
i  ii 

5  4 

7.2 

4 

5-2 

6.1 
4-3 

99 

lO.g 

9.3 

99 

10.4 
9-3 

99 

IO.4 

9-4 

4.06 

4.10 

4.08 

2.56 

2.81 

2 

•84 

1.05 
.66 

1.72 

1.86 
13 

5-8 

75 
4-7 

5-7 

6-7 
5 

9-7 

IO.2 

8-7 

9-7 

10  4 
93 

9-7 

10.2 

9-3 

4.10 

4.11 

4.1 

2 

2.18 
1.69 

•72 

.89 
.6 

1.28 

i  38 

I.  01 

63 

12.3 
4-2 

6-3 

9.2 
4-3 

10.5 

11.7 
99 

10.4 

10.9 
94 

10  4 

10.8 
99 

4-6 

4  39 

4-5 

I.38 

i-99 
•49 

•49 

.76 
.16 

.89 

1.27 
•33 

55 

6.7 
4-6 

6-4 

7-5 
5-6 

10.3 

10.9 
9.9 

10.6 

ii 
99 

10.4 

10.8 

10 

53 

3  .88 

459 

•45 

•49 
•33 

•17 

•25 

.12 

.27 

•43 

.21 

whole    period. 


1123 

1  3  3 

5 

92 
3-9 

,"  7 

I  76 

ii 

78 

110  8 
9.4    8.6 

2-37 

3-64 
•33 

.82 
^253 

1.4 

.12 

T89~ 

i-55 

47! 

2.45 

.21 

~52~ 

729.41 

ist  to  3 ist,  of  about  2^  Ib.  per  day.  It  changed  very  little  in  June; 
but  fell  off  very  rapidly  in  July  till  the  first  of  August,  when  the 
cow  was  dry. 

As  a  rule  the  weights  of  the  morning  milk  only  varied  one- 
fourth  to  one  Ib.  from  that  of  the  preceding  morning.  The  greatest 
variation  of  this  kind  was  three  and  one-half  Ib.,  which  happened 
only  once.  This  was  also  true  of  the  night  milking.  A  comparison 
of  the  two  milkings  on  any  one  day  shows  that  while  they  were 
generally  about  the  same  in  quantity,  there  were  times  when  one 
would  be  high  and  the  other  low.  The  greatest  difference  of  this  kind 
was  6  Ib.  This  occurred  in  the  two  milkings  of  the  day  the  cow  was 
bred. 

SOLIDS    OF    THE    MILK. 

The  average  per  cent  of  solids  in  the  614  samples  of  milk  of 
this  cow  for  the  whole  period  of  lactation  was  14.4,  the  highest  22.4, 
and  the  lowest  11.9,  a  difference  of  9.5.  The  difference  between  the 
extreme  per  cents  of  solids  in  the  daily  milk,  however,  was  6.4,  and 
between  the  daily  average  per  month  3,  showing  that,  although  the 


144  BULLETIN  xo.   24.  [February, 

quality   of   the  milk   may  take   a  sudden   jump   up   or  down   at   some 
particular  milking,  the  change  is  not  permanent. 

There  was  only  one  sample  of  milk  that  showed  11.9  per  cent 
solids;  and  but  9  out  of  the  614  that  went  below  13  per  cent  solids. 
A  selection  of  the  milks  containing  a  high  per  cent  of  solids  shows 
that  four  samples  reached  20  per  cent  solids,  but  only  one  was  22 
per  cent,  and  that  26  samples  were  over  17  per  cent  of  solids. 

When  the  cow  was  fresh  and  gave  the  most  milk,  it  contained 
the  minimum  amount  of  solids.  The  table  shows  that  the  milk 
gradually  increased  in  richness  of  solids  as  the  period  of  lactation 
advanced,  until  it  reached  the  maximum,  when  the  flow  of  milk 
was  at  its  minimum,  and  the  cow  drying  up.  The  per  cent  of  solids 
went  as  low  as  14.9  at  one  milking  during  the  last  week  of  the  lacta- 
tion period,  and  up  to  19.9  a  difference  of  5;  while  in  the  first  week 
there  was  a  variation  of  only  2.3.  This  indicates  that  the  milk  of 
this  cow  was  subject  to  quite  extreme  changes  in  quality,  especially 
when  the  quantity  was  small.  A  comparison  of  the  per  cent  of 
solids  found  in  the  morning  milkings  of  each  month,  shows  that 
with  the  exception  of  3  months  there  was  a  difference  of  i.S  to  3.8 
per  cent  between  the  extremes.  The  greater  differences  observed 
in  the  3  months  were  5.6,  5.8,  and  6.4.  The  variations  of  5.6  and 
5.8  per  cent  occurred  six  days  apart,  at  the  time  when  the  heavy 
grain  ration  was  begun.  The  difference  of  6.4,  between  the  highest 
and  lowest  of  solids,  was  observed  in  the  milk  of  the  last  month, 
when  the  cow  was  drying  up.  The  night  milkings  showed  similar 
variations.  A  study  of  the  variations  that  occurred  in  the  daily  milk, 
or  the  sum  of  the  analyses  of  the  morning  and  night  milk  divided  by 
two,  shows  a  much  smaller  difference  between  extremes.  When  the 
heavy  grain  feeding  was  begun,  there  was  a  difference  of  4.1  per 
cent  solids  between  the  extremes  of  that  month,  and  of  4.6  in  the 
last  month  of  the  period  of  lactation.  With  the  exception  of  these 
two  months  there  was  a  difference  of  only  1.3  to  3.1  between  the 
highest  and  lowest  daily  per  cent  of  solids  every  month.  The  varia- 
tions occurred  quite  as  often  above  as  below  the  average,  making 
the  quality  of  the  milk  from  one  month  to  another  about  the  same, 
except  that  it  gradually  increased  in  richness  up  to  the  end  of  the 
period  of  lactation.  This  is  illustrated  by  the  figures  of  the  foregoing 
table  and  the  diagram  after  page  152. 

BUTTER    FAT    IN    THE    MILK. 

The  average  per  cent  of  fat  in  the  milk  of  this  cow  was  5; 
the  highest  12.3;  the  lowest  2.9  —  a  difference  of  9.4.  As  has  been 
stated  before,  the  difference  between  the  highest  and  lowest  per  cent 
of  solids  in  the  milk  was  9.5,  indicating  that  the  fat  is  naturally  the 
variable  quantity  in  the  solid  matter  of  milk.  The  lowest  per  cent 
of  fat,  2.9,  was  found  in  only  one  sample  of  milk,  that  of  the  morn- 
ing of  November  28th.  Only  5  out  of  the  614  samples  contained 


1893-]  VARIATIONS     IN    MILK.  145 

less  than  3.5  per  cent  fat.  The  samples  of  milk  which  contained 
the  most  fat  were  nearly  all  from  the  latter  part  of  the  period  of 
lactation,  only  one  sample  reached  12  per  cent  fat,  four  were  10 
per  cent  or  over,  and  25  were  7  per  cent  or  over. 

The  table  and  the  diagram  show  that  during  the  first  six  months 
after  calving  the  milk  contained  between  4  and  5  per  cent  of  butter  fat; 
after  that  time  the  average  per  cent  was  between  5  and  6.  The  differ- 
ence between  the  highest  and  lowest  per  cent  of  fat  in  the  morning 
milkings  of  the  different  months  varied  from  1.4  to  3.2,  with  the  excep- 
tion of  two  months,  when  the  difference  was  7.2  and  S.i.  These  were 
the  same  months  when  the  greatest  variation  in  solids  was  noticed. 
The  night  milk  showed  the  same  peculiarities,  while,  excepting  these 
two  months,  the  dailv  milk  of  each  month  showed  a  difference  of  only 
from  .9  to  3  between  the  extreme  per  cents  of  fat  observed  in  any  one 
month.  During  the  last  two  weeks  of  the  period  of  lactation,  when  the 
cow  gave  only  2  to  5  Ib.  of  milk  daily,  the  per  cent  of  fat  was  all  the 
way  from  6  to  9.4  and  varied  greatly  from  day  to  day.  There  were 
also  several  milkings  at  different  times  in  the  period  of  lactation  when 
the  milk  contained  7,  9,  10  and  1 1  per  cent  of  fat.  At  such  times  the 
amount  of  milk  was  neither  very  much  above  or  below  the  average  for 
that  time.  The  per  cent  of  fat  in  the  morning  milk  was  not  greater  or 
less  than  in  the  night  milk  for  any  great  number  of  days.  During 
short  periods  of  3  to  10  days  in  the  year  there  would  be  a  difference  in 
the  fat  contents  of  the  morning  milk  as  compared  with  the  night  milk 
for  the  same  time,  but  it  soon  changed  and  neither  one  was  higher  or 
lower  than  the  other  for  more  than  10  days  at  a  time. 

SOLIDS  NOT  FAT. 

These  include  the  casein,  milk  sugar,  and  mineral  substances  of  the 
milk.  The  average  quantity  contained  in  the  milk  of  this  cow  was  9.4 
per  cent.  The  lowest  per  cent  found  in  any  sample  of  milk  during  the 
year  was  7.6;  the  highest,  1 1.7 — a  difference  of  4.1.  Only  3  samples  of 
this  cow's  milk  went  below  8  per  cent  of  solids  not  fat  and  24  above 
10.5  per  cent.  The  diagram  and  the  figures  in  the  table  show  that  this 
constituent  of  the  milk  did  not  make  such  extreme  variations  as  were 
observed  in  the  butter  fat.  The  per  cent  of  solids  not  fat  in  the  milk 
was  very  uniform  throughout  the  whole  period  of  lactation.  It  varied 
from  9  to  9.5  in  the  first  three  months,  gradually  rising  to  9.5  to  10 
during  the  next  six  months  and  was  10  to  10.5  the  last  month  of  the 
milking  period.  The  per  cent  of  solids  not  fat  was  generally  .2  to  .5 
higher  in  the  morning  than  in  the  night  milk,  except  during  the  last 
two  months  of  the  period  of  lactation  when  there  was  no  uniform  differ- 
ence either  way. 

Excepting  a  few  times  when  analyses  were  lost,  the  milk  of  this 
cow  was  tested  307  days.  As  there  were  two  milkings  each  day  this 
made  614  samples.  The  average  of  all  tests  showed  the  milk  to  have 


146 


BULLETIN    NO.    24. 


^February •, 


the  following  composition:  solids,  14.4;  fat,  5;  solids  not  fat,  9.4  per 
cent.  The  highest  and  lowest  percentages  found  in  these  samples  were, 
solids,  11.9  to  22.4;  fat,  2.9  to  12.3;  solids  not  fat,  7.6  to  11.7. 

The  following  table  has  been  constructed  from  the  record  of  all 
these  samples  to  show  that  the  extreme  per  cents  were  exceptional  and 
that  most  of  the  milk  was  of  a  uniform  quality.  The  table  shows  how 
many  of  the  614  samples  of  this  one  cow's  milk  were  above  15  per  cent 
and  below  13.5  per  cent  solids;  above  5.5  and  below  4  per  cent  fat; 
above  10  and  below  9  per  cent  solids  not  fat. 

NUMBER  OF  SAMPLES  OUT  OF  614  IN  WHICH  PERCENTAGES  OF  SOLIDS,  FAT,  AND  SOLIDS 
NOT  FAT  WERE  ABOVE  OR  BELOW  CERTAIN  STANDARDS. 


Per  cent 
solids. 

Per  cent  solids 
over  15  and 
under  13.5. 

Per  cent 
fat. 

Per  cent  fat 
over  5.5  and 
under  4. 

Per  cent 
solids 
not  fat. 

Per  cent,  solids 
not  fat  over  10 
and  under  9. 

a.m. 

p.m. 

*Daily 
av. 

a.m. 

p.m. 

37 
26 
ii 

9 

i 

*Dail> 
av. 

a.m. 

p.m. 

*Daily 
av. 

I5-I5.5 
I5-5-I6 
16-17 
17-18 
18-20 

20 

Total  

35 
3i 
26 
6 

2 

3 

3i 
10 

19 

4 
ii 

i 

28 
27 

22 
9 

3 

5-5-6 
6-6.5 

6.5-7-5 
7-5-9 

10-12 

29 

21 

16 
3 
3 

35 
23 
13 

4 

10-10.5 
10.5-11 
11-11.7 

37 

12 

27 
10 

2 

25 
ii 

36 

103 

76 

89 

72 

84 

75 

49 
16 

39 

•[Percentage 
of  the  whole. 

3° 

25 

9 

4 

29 

23 

27 

24 

12 

ii 
ii 

!3-5-i3 
13-12.5 

Total  

19 
4 

X4 

4-3-5 

2       C       0 

13 

2 

2 

2 

2 

9-8.5 
8.5-8 
8-7-5 

3 

i 

30 

5 

2 

ii 

23 

13 

M 

15 

4 

2 

4 

37 

fPc^rcentage 
of  the  whole. 

7 

4 

4 

5 

I 

i 

12 

4 

*The  daily  average  means  here  the  per  cent  found  each  day  by  dividing  by  two 
the  sum  of  the  per  cents  found  in  the  morning  and  night  milk  of 'each  day. 

f 307  is  taken  for  the  whole  number  of  samples  in  calculating  this  percentage. 

A  study  of  this  table  shows  that  the  quality  of  the  morning 
and  night  milk  varied  about  the  same.  From  one-fourth  to  one- 
third  of  all  the  samples  contained  over  15  per  cent  solids,  but  most 
of  these  were  between  15  and  17;  only  very  few  went  over  17  per 
cent,  while  4  to  7  per  cent  of  the  whole  number  of  samples  went 
under  13.5  per  cent,  and  a  still  less  number  under  13  per  cent  solids. 

About  one-fourth  of  all  the  samples  had  over  5.5,  a  very  few 
were  above  7,  and  only  four  had  10  to  12  per  cent  fat.  There  were 
only  four  samples  below  3.5  per  cent,  and  17  out  of  the  614,  between 
3.5  to  4  per  cent  fat. 

The  limits  of  variation  in  the  solids  not  fat  are  still  narrower. 
Only  two  samples  had  over  n  per  cent,  and  3  under  8  per  cent. 


VARIATIONS    IX    MILK. 


Cow  No.  3  —  Shorthorn. — The  weighing  and  testing  of  this 
cow's  milk  was  made  every  day  for  fourteen  months.  This  unusually 
long  period  of  lactation  was  due  to  her  failure  to  get  with  calf.  It 
makes  her  record  all  the  more  useful,  as  evidence  of  what  the  quality 
of  milk  is  under  these  conditions,  which  occur  more  or  less  frequently 
among  cows.  She  was  four  years  old,  and  her  live  weight  varied 
from  888  to  1,160  Ib. 

WEIGHT   OF    MILK. 

The  milk  of  this  cow  was  weighed  every  milking,  but  the  analyses 
were  made  on  one  daily  sample,  which  was  a  mixture  of  equal  parts 
of  the  morning  and  night  milk.  The  total  quantity  of  milk  produced 
was  6,193  Ib.  This  contained  228  Ib.  fat,  equal  to  274  Ib.  butter. 
The  most  milk  given  on  any  day  was  26.5  Ib.  in  July,  the  first 
Cow  No.  3,  SHORTHORN. — THE  DAILY  AVERAGE  AND  EXTREMES  OBSERVED 

DURING  EACH  MONTH. 

Weighing  and  Testing  of  Milk  began  July  6,  1891,  and  continued  to  September  4, 
1892 — 428  days. 


Pounds. 

Per  cent. 

Pounds. 

r 

§' 

Milk. 

Solids. 

Butter 
fat. 

Solids 
not  fat. 

Casein 

Solids 

Butter 
fat. 

Not 
fat. 

W 

> 

w 

. 

W 

. 

W 

. 

W 

^ 

M 

rt? 

|^ 

X 

rj 

X 

v^ 

X 

j£j 

X 

*£ 

^ 

X 

*\7 

X 

^ 

? 

o> 

CD 

-CD 

1-1 

? 

CD 

CD 

CD 

July  6-31 

993 

24 

26.5 
20.5 

12.2 

13-4 

n-7 

3-7 

4-4 

2-7 

8.5 

10.3 

8.5 

3-23 

2-93 

3.56 

2-45 

.89 

1.17 
.62 

2.04 

August.  . 

974 

22.5 

25 

21 

II-9 

12.5 
n-4 

3-2 

3-9 
2.7 

8-7 

9 

8 

3  03 

2.68 

3-i8 
2.32 

.72 

•97 
•57 

1.96 

Sept  

957 

17.8 

22-5 

12.  1 

13-3 

H-4 

3-3 

4-2 

2.8 

8.8 

9-i 

8-4 

3-05 

2-15 

2.78 
i-45 

•59 

•85 
•35 

1-56 

Oct  

958 

13-9 

l6-5 
II 

12.9 

14-5 

12 

3-7 

4-4 
2.9 

9.2 

10.4 

8-5 

3-33 

i-79 

2.09 

•51 

.66 
•38 

1.28 

Nov  

920 

11.9 

14 

8-5 

12.9 

14.1 
12 

3-7 

^ 

9.2 

10.3 
8.8 

3.26 

i-53 

1.9 
i.i 

•44 

•67 
•29 

1.09 

Dec  

920 

12.  1 

16 

10 

12.8 

14 

10.8 

3-8 

4-9 

3 

9 

9.6 

7-2 

2.92 

i-55 

2.  II 

i-33 

•46 

.6 
•34 

1.09 

Jan  

927 

16 

17.7 
M 

I3-I 

14.2 
12.5 

3-7 

4-6 

2-7 

9-4 

10.2 

9 

3-34 

2.10 

2.41 

1.84 

•58 

•76 
•44 

1-52 

Feb.   ... 

1035 

16.1 

17.7 
13-5 

13  2 

14.9 
12.3 

3-6 

5-8 
32 

9-6 

IO 

8.6 

3-47 

2.12 

2.32 

i  75 

•58 

84 

.51 

1-54 

March.. 

1047 

14-3 

16 
12.5 

13-5 

14.4 
12.9 

3-8 

47 
3-4 

9-7 

IO.I 

9-3 

3.52 

' 

2.12 

i-75 

•54 

.61 

•5 

i-39 

April..  .  . 

1054 

13-8 

16.5 
ii.  5 

13-5 

12.7 

4 

5-8 
3 

9-5 

10.5 

3-49 

1.86 

2.13 
i-59 

•55 

•72 
.46 

1.31 

May  

1079 

J4-5 

17.2 

10 

13-3 

14-3 

12.8 

3-8 

4-6 
3-4 

9-5 

9-9 
8-9 

3-89 

i-93 

2.31 
i  39 

•55 

•7 
•44 

1-38 

June.  .  .  . 

1105 

12.  1 

14 
9-2 

I3-I 

I7.8 

12.  1 

3-9 

4.6 

3-2 

92 

9-9 
8-3 

3-42 

1.58 

2  31 
i.  ii 

•47 

•57 
•35 

i.  ii 

Juy.... 

1118 

93 

12.2 

6 

13  3 

16.2 

12 

4-2 

6.2 
2.8 

9-i 

ii.  i 

7-4 

3-8 

1.24 

1.62 
.82 

•39 

.6 

•27 

•85 

August.  . 

1130 

6.4 

9-7 
3-5 

13-7 

17 
I2.4 

4-7 

is* 

8.2 

3-87 

.87 

1-4 

•5 

•  3 

•  5 

.16 

•57 

For  the  whole  period. 

26.5 

17-81 

7-9 

11-3 

3.56 

1.17 

14-4     3-5 

12.8 

10.  8)3.7 

2-5 

9-2|    7-2 

1.85 

•5 

•53 

.16 

1.32 

Totals  .  .                 6193.3 

794-37 

227.8  [566.57 

148  BULLETIN    NO.   24.  \_Feb  ruary^ 

month  after  calving.  The  preceding  table  shows  that  the  milk  decreased 
in  quantity  but  little  in  August,  the  second  month  of  the  lactation  period, 
but  gradually  diminished  in  the  third  and  fourth  months,  till  the  fifth 
month,  November,  when  she  gave  only  about  12  pounds  of  milk  daily. 
The  quantity  increased  during  the  winter  months  of  stable  feeding, 
on  a  liberal  grain  ration,  and  it  was  not  till  the  next  July  that  the 
milk  flow  was  so  small  as  it  had  been  in  November.  In  August 
and  September,  the  thirteenth  and  fourteenth  months,  the  flow  of 
milk  diminished  till  the  cow  "  went  dry." 

The  average  amount  of  milk  given  per  day,  for  the  whole  period 
of  lactation,  was  14.4  lb.,  and  for  nine  months  of  this  time  the  daily 
average  per  month  varied  very  little  from  this  figure;  for  one  month 
it  was  2.5  lb.  more,  and  another  month  1.7  lb.  less. 

The  minimum  amount  milk  given  in  one  day  was  3.5  lb.,  and 
there  were  several  days  at  the  end  of  the  milking  period  when  she 
gave  only  four  pounds. 

No  great  variation  was  observed  in  the  weight  of  milk  produced 
from  day  to  day  in  any  month.  There  was  a  difference  of  7  and  10 
lb.  between  the  highest  and  lowest  daily  milk  of  two  months;  but 
in  the  other  twelve  months  this  difference  between  extremes  was 
from  3.5  to  6  lb.  The  daily  milk  was  increased  6  lb.  by  a  heavy 
grain  ration  in  winter,  and  again  by  change  from  stable  feeding 
to  pasture. 

SOLIDS   OF    THE    MILK. 

The  average  per  cent  of  solids  in  the  428  samples  of  this  cow's 
milk  was  12.8;  highest,  17.8;  lowest,  10.8 — a  difference  of  7.  The 
table  shows  that  between  the  daily  averages  per  month  there  was 
only  a  difference  of  1.8  per  cent  of  solids.  There  was  only  one 
sample  that  had  17.8  per  cent  of  solids,  and  two  that  went  as  low 
as  10.8  per  cent.  Thirty-four  samples  were  below  12  per  cent  (11.9 
to  11.4);  28,  above  14  per  cent;  but  of  these  latter  only  7  went  above 
15  per  cent.  There  was  a  slight  increase  in  the  amount  of  solids 
in  the  milk  from  the  first  to  the  last  part  of  the  milking  period; 
but  the  table  shows  that  the  per  cent  of  solids  was  quite  uniform 
through  all  the  changes  of  feed  and  season  in  the  14  months  of 
the  trial. 

BUTTER    FAT    IN    THE    MILK. 

The  average  per  cent  was  3.7  in  the  milk  of  this  cow;  highest, 
7.9;  lowest,  2.5  per  cent  —  a  difference  of  5.4.  Only  one  sample 
went  as  low  as  2.5  per  cent,  and  17  samples  gave  less  than  3  per 
cent  (2.7  to  2.9).  One  sample  only  reached  7.9  per  cent;  three, 
6  to  7  per  cent;  sixteen,  5  to  6  per  cent,  and  seventeen  4.5  to  5  per 
cent  —  making  out  of  a  total  of  428  samples  of  milk  from  this  cow 
56  that  were  outside  the  limits  of  3  to  4.5  per  cent  fat.  As  a  rule 
the  minimum  per  cent  of  fat  was  found  in  the  milk  when  the  cow 
WAS  fresh,  and  gave  the  largest  quantity,  and  the  maximum  per  cent 


VARIATIONS    IN    MILK. 


I49 


of  fat  was  during  the  last  part  of  the  milking  period.  The  table  shows, 
however,  that  there  were  days  in  the  last  month  of  the  period  of 
lactation  when  the  milk  contained  only  2.9  per  cent  fat. 

SOLIDS    NOT    FAT. 

The  average  per  cent  was  9.2;  highest,  11.3;  lowest,  7.2  per 
cent.  With  the  exception  of  these  two  extremes,  no  sample  went 
below  8  per  cent,  or  above  10.5  per  cent.  There  were  only  10 
other  samples  below  8.5  per  cent,  and  seven  above  10  per  cent, 
making  -410  out  of  the  428  samples  that  contained  between  8.5  and 
10  per  cent  of  solids  not  fat.  This  illustrates  what  was  also  found 
true  with  cow  No.  i,  that  the  per  cent  of  solids  not  fat  is  very 
uniform,  and  that  the  fat  is  the  variable  quantity  in  the  milk  solids. 

The  milk  of  this  cow  was  quite  uniform  in  quality  throughout 
the  whole  milking  period,  and  the  sudden  changes  frequently  observed 
in  the  milk  of  cow  No.  I  did  not  occur. 

Coivs  No.  16  and  18 —  Shorthorns^  ages  8  and  7  years. — The 
tables  show  that  these  two  cows  were  very  much  alike  in  the  quantity 

Cow  No.  16,  SHORTHORN. — THE   DAILY  AVERAGE   AND  EXTREMES   OBSERVED  DURING 

EACH  MONTH. 

Weighing  and  Testing  of  Milk  began  August  31,  1891,  and  continued  to  July  27, 
1892—332  days. 


Pounds. 

Per  cent. 

Pounds. 

r 

i' 

Milk. 

Solids. 

'Butter 
fat. 

Solids 
not  fat. 

o 

Solids. 

Butter 
fat. 

Not  fat. 

~ 

w 

W 

W 

W 

0 

M 

K 

W 

^ 

X 

^ 

x 

•< 

x 

^ 

x 

^ 

x 

< 

x 

< 

x 

r1 

r* 

•t 

"* 

1-1 

^ 

Sept.. 

1127 

22.7 

37-5 

12.5 

14 
ii.  i 

3-5 

4-6 
2.4 

9 

10.7 
8.5 

3.22 

2.83 

4-17 

2.22 

•79 

1.03 
•  5 

2.04 

3-27 
1.67 

Oct.. 

1104 

15-5 

21.  5' 

8 

13-2 

14-5 
12.3 

3-9 

4-9 

3-2 

9-3 

9.7 

8.9 

3.46 

2.04 

2.71 
•84 

.6 

.8 
.42 

1.44 

i-97 
•32 

Nov... 

1068 

12.9 

16 
9 

13-5 

15-8 

4 

5-8 
3.2 

9-5 

10.  3 
8.9 

3.65 

i-74 

2.15 
I  .  19 

•52 

.85 
•35 

1.22 

*'.*4 

Dec... 

1041 

11.9 

13-5 
ii 

13-3 

14.5 

12.2 

3-9 

5-2 
3-4 

9-4 

10 

8.8 

3-33 

1.58 

1.88 
1.43 

.46    '63l 

I.  12 

1.25 
•97 

Jan... 

1036 

12.2 

14 
ii 

13-2 

13-9 
12.6 

3-9 

4-5 
3  4 

9-3 

9.8 

9 

3-34 

1.61 

1.84 
1.44 

.47 

•56 
.41 

I.I4 

1.28 

i 

Feb  . 

1057 

10.3 

13-5 

7-5 

13-5 

14.4 

12.  5 

3-9 

5-4 
3-3 

9.6 

9-6 
8-9 

3-2 

i   39 

i-77 
•96 

•  4 

.62 
•25 

•  99 

1.22 
•71 

March 

1063 

10.  1 

8 

13-4 

14.3 

12.  I 

3-9 

4-7 
3-i 

9-5 

9-8 
8.9 

3-6 

1-35 

1-53 
1.07 

•  39 

•47 
•33 

.96 

I-I5 

•74 

April  . 

1095 

9-3 

13-2 

6.2 

13-9 

15-6 

12.5 

4-1 

5-3 
2.9 

9-8 

10.6 
9.1 

3.63 

1.29 

1.69 

•  93 

•  38 

.6 
.28 

•  91 

1.2 
.64 

May.. 

n76 

5-9 

8.5 

2.2 

14 

19.4 
II 

4.1 

9.2 
1.8 

9-9 

10.2 

9-2 

4-2 

•  83 

1.36 
•34 

.24 

.36 
.09 

•  59 

.8 
.16 

June.. 

1195 

6 

7-5 
5 

13-4 

I4.6 

12.5 

3-9 

4.6 

9-5 

10.6 

4-°5 

.8 

i.og 
.67 

•  23 

•34 
.19 

•57 

•75 
•47 

July  .  . 

1236 

6.1 

9 

5 

13-7 

M-7 

ii  -7 

4 

4-8 

I    r 

9-7 

10 

8.5 

4-45 

.83 

I  .02 

•54 

•24 

.36 
•13 

1    8 

•59  ;l8 

For  the  whole  period. 

II.  2 

37.5 

2.2 

13-3 

19.4 
ii 

3.S 

9.2 
1.8 

9-4 

10.7 

8.5 

*.« 

>4:^ 

•44 

':3U 

3-27 
16 

Total 

3738.2 

495.62 

145.8 

349  82 

1 5° 


BULLETIN     NO.    24. 


[February  ^ 


and  quality  of  their  milk;  but  quite  different  from  the  other  four 
cows.  They  each  gave  something  over  3,000  Ib.  of  milk,  and  it 
contained,  No.  16,  146  Ib.,  and  No.  18,  115  Ib.,  butter  fat.  Previously 
to  this  year  they  had  been  used  for  raising  calves,  and  consequently 
had  been  milked  very  little.  This  undoubtedly  accounts  for  this  poor 
record.  The  tables  show  that  there  was  a  great  variation  in  the  daily 
weight  of  milk  given  each  month.  This  was  particularly  true  when 
the  cows  were  fresh  in  milk.  During  the  first  month  after  calving 
No.  1 6  varied  from  25  to  10.5  Ib.,  and  No.  18  from  37.5  to  19  Ib. 
milk  per  day.  There  were  very  unexcusable  deviations  in  the  milk 
all  through  the  period  of  lactation.  This  was  probably  caused  by 
their  lack  of  training  as  milch  cows.  They  often  refused  to  give 
down  their  milk.  The  analyses  show  that  their  milk  was  of  average 
quality.  The  per  cents  of  solids  and  of  fats  varied  more  than  in 

Cow  No.   18,   SHORTHORN. — THE  DAILY  AVERAGE   AND   EXTREMES  OBSERVED  DURING 

EACH  MONTH. 

Weighing  and  testing  of  milk  began  August  31,  1891,  and  continued  to  August  7, 
1892 — 342  days. 


Pounds. 

Per  cent. 

Pounds. 

s 
§ 

r 

CD 

Milk. 

Solids. 

Butter 
fat. 

Solids 
not  fat. 

n 

y      £/) 

CD 

Solids. 

Butter      XT   .  r  .. 
,  4          Not  fat. 
lat. 

•3" 

3 

, 

r^> 

> 

W 

W 

W 

5 

W 

W 

W 

? 

X 

< 

^ 

X 

? 

X 

P> 

J 

X 

? 

X 

J 

£ 

r* 

r* 

r1 

r1 

• 

r1 

• 

1-1 

* 

Sept.. 

1140 

19.1 

25 
10.5 

12.2 

14.8 

II.  2 

3-3 

6.4 

2.2 

8.9 

9-3 
8.4 

3-19 

2  33 

3-27 
1.25 

•  63 

1.41 

i.7 

2-37 
•94 

Oct...  1123 

13-3 

17 

8-5 

12.8 

14-7 
10.2 

3-6 

2.6 

9-2 

10.8 
8.7 

3-45 

i.7 

2.27 
i.i 

.48 

.66 
•34 

I  .22 

1.78 
•76 

Nov  .  . 

III4 

10.5 

16 
6.5 

I3-I 

15 
12.  I 

3-8 

5-4 
2.7 

9-3 

10 

8  6 

3-43 

1-37 

2.15 
.85 

.40 

•65 

•  23 

•97 

'62 

Dec... 

II3I 

9-2 

13 

4 

13 

15 

ii.  8 

3-7 

5-5 

2.6 

9-3 

10.8 

8.2 

3-15 

1.19 

1.78 
•  52 

•34 

•14 

.85 

1.27 
•38 

Jan... 

1130 

9-1 

ii 

7-7 

13-5 

14-5 

12.6 

4 

4.8 
3-3 

9-5 

10.  I 

9 

3-34 

1.23 

1-47 

1.  06 

•  36 

•45 
.28 

.87 

1.05 

•75 

Feb... 

1138 

8.2 

10 

6.5 

13.2 

T4.6 

12.4 

3-6 

4-9 
3 

9-6 

10 

8.9 

3-2 

i.  08 

1.35 
.85 

.29 

•39 

•25 

•79 

.96 
•59 

March 

II44 

7-1 

9 

5-7 

13-6 

14.8 

ii.  8 

4 

5-2 

3-4 

9-6 

9-9 

8.4 

3-45 

•  96 

1  .26 
.8 

.28 

•43 
.24 

.68 

.85 
•53 

April  . 

1168 

6.2 

8.2 

4.2 

I4.I 

16.5 

12.3 

4-3 

6.2 

2.7 

9.8 

10.5 
9-2 

3-63 

.87 

1.09 
.61 

.26 

•46 
•  M 

.61 

•79 
.42 

May.. 

1224 

5-9 

7-2 

3 

I3.6 

17.8 

ii.  8 

4 

8.1 

2.8 

9-6 

10 

8.4 

4.12 

.8 

i.  06 

•37 

.24 

•42 
.  i 

•56 

.27 

June  .  . 

1243 

6  8 

8.2 

4-5 

13 

12.  I 

3-8 

5-4 
2-7 

9-2 

9-8 

8-4 

3.65 

•  89 

1.05 

•54 

.26 

•  36 
•  14 

.63 

•77 
•4 

July  .  . 

1270 

3-8 

6 

1.2 

13-5 

15-3 
12.2 

4 

5-6 

2.8 

9-5 

ii 

8 

4.19 

•5i 

.86 
•  15 

•  15 

•  36 
.04 

.6 

For  the  whole  period. 

i          ; 

1 

8.9 

25 

I  .2 

I3-I 

17.8 
10.2 

3-7 

8.1 

2.2 

9-4 

ii 
8 

1.17 

3-27 
•15 

•33 

1.41     -8    2.37 
.04         *    .11 

Total  . 

3069.3 

399-8 

115.3        284.5 

^93-] 


VARIATIONS    IN    MILK. 


the  milk  of   any  of   the  other   cows,  except  No.    i,  whose   milk  was 
much  richer. 

The  per  cent  of  solids  not  fat  in  the  milk  of  these  cows,  as  in 
that  of  the  others,  was  the  most  constant  constituent  of  the  milk, 
and  the  per  cent  of  fat  was  the  most  variable. 

Unlike  the  other  cows'  milk,  that  of  these  two  did  not  increase  in 
richness  very  much   in   the   last  part  of  the  period  of  lactation.     The 
erratic   nature   of   these   cows  is   illustrated  by  comparing  the  extremes 
observed  in  the  first  and  last  month  of  their  milking  period. 
Cows  No.  1 6  AND  No.  18. — EXTREMES  IN  MILK  PRODUCT  OF  FIRST  AND  LAST  MONTHS. 


Cow  No.  16. 

Daily 

Per 

cent 

Cow  No.  18. 

Daily 

Per 

cent 

First  month. 

milk,  Ib. 

Solids 

Fat. 

First  month. 

milk,   Ib. 

Solids. 

Fat. 

Highest  

17    "5 

14 

4.6 

Highest.  .  . 

2^ 

14  8 

6  4 

Lowest  

19 

ii  .  i 

2.4 

Lowest  

IO  S 

II  2 

2  2 

Last  month. 

.Last  month. 

Highest 

Q 

M7 

4    8 

Highest 

6 

T  C     0 

c  6 

Lowest  .  . 

5 

II  .7 

i  Q 

Lowest  .  . 

1.2 

12.2 

2.8 

The  uncommon  features  illustrated  in  this  table  are  several:  First, 
that  there  should  be  such  a  variation  in  the  daily  weight  and  composition 
of  milk  in  the  first  month  of  the  milking  period;  second,  that  the  per  cent 
of  fat  should  be  so  high  in  the  first  month  when  the  average  of  the 
cow's  milk  was  3.5;  third,  that  the  quality  of  the  milk  in  the  two 
months  should  be  so  nearly  the  same;  and  fourth,  that  milk  of  such  a 
low  per  cent  of  solids  and  fat  should  be  produced  in  the  last  month  of 
the  period  of  lactation. 

Several  other  very  striking  illustrations  of  great  variations  are 
shown  in  the  following  table: 

Cows  No.  16  and  18.  — SOME  EXTREME  VARIATIONS  IN  MILK  PRODUCT. 


Per  cent. 

Per  cent. 

Cow  No.    16. 

Milk, 
Ib. 

Solids. 

Fat. 

Solids 
not  fat 

Cow  No.   18. 

Milk, 
Ib. 

Solids. 

Fat. 

Solids 
not  fat 

Oct.     9 

18.5 

13-4 

39 

9-5 

Sept.  17 

17-5 

11.4 

2.7 

87 

IO 

6-5 

12.9 

3-6 

9-3 

18 

10.5 

ii  9 

3 

8-9 

ii 

8 

12  4 

3-2 

92 

19 

22 

14.8 

6.4 

8.4 

12 

16.5 

12  4 

3-4 

9 

20 

I6.5 

12.3 

36 

8-7 

J3 

17-5 

13  3 

4 

9-3 

21 

19  5 

ir  7 

2.8 

8.9 

April  30 

8 

14.2 

4.2 

10 

April  30 

6-5 

13-7 

42 

9-5 

May     i 

8-5 

13  7 

4-3 

9-4 

May     i 

5-7 

13-2 

39 

9-3 

2 

4-5 

12 

26 

9  4 

2 

42 

ii.  8 

34 

8.4 

3 

5 

II 

1.8 

9-2 

3 

5 

12.3 

2.8 

9  5 

4 

4.2 

12 

2-5 

9-5 

4 

3 

12.6 

32 

9-4 

5 

3-2 

12-7 

3 

9-7 

5 

3-5 

13 

36 

9-4 

6 

7 

I9.4. 

9  2 

10.2 

6 

5-2 

17.8 

8.1 

97 

7 

2.2 

15-4 

56 

9.8 

7 

3 

136 

4 

96 

8 

65 

14-5 

4.6 

9  9 

8 

4-5 

13-1 

3-4 

9-7 

9 

6-5 

M 

4-2 

9.8 

9 

7 

I4  2 

4-5 

9-7 

IO 

6 

I4.3'l     4.4 

99 

10 

5-5 

136    1     3.8 

9.8 

152  BULLETIN   NO.   24.  [  February, 

Cow  No.  16  had  been  giving  from  16  to  18  Ib.  milk  daily,  and  the 
sudden  change  to  6.5  and  8  Ib.  Oct.  loth  and  nth,  and  then  a  return  to 
her  usual  quantity  without  much  change  in  the  quality  of  the  milk  is  a 
variation  that  the  other  cows  did  not  show,  except  No.  18  which  made 
nearly  an  equal  variation  in  September.  A  sudden  change  from  10.5 
to  22  Ib.  milk  was  recorded  on  Sept.  i8th  and  I9th  ;  the  quality  of  the 
milk  changed  also  from  1 1.9  to  14.8  per  cent  solids  and  from  3  to  6.4  per 
cent  fat.  Afterward  the  amount  and  richness  of  the  milk  was  about 
what  it  had  been  before  this  break  and  continued  quite  uniform. 

When  the  cows  were  first  turned  out  to  pasture  they  were  not  fed 
grain  at  milking  time,  as  had  been  the  custom  previously.  The  feed  in 
the  pasture  was  ample,  and,  with  the  exception  of  these  two  cows,  the 
flow  of  milk  suddenly  increased  in  quantity.  The  lower  part  of  the 
table  shows  how  these  two  cows  were  affected  by  the  change  to  pasture 
and  absence  of  grain  when  milked.  They  gave  less  milk  of  poorer 
quality  than  before  and  continued  to  do  so  for  a  week  with  the  exception 
of  one  day,  May  6th,  when  both  amount  and  richness,  especially  the  lat- 
ter, were  very  high.  May  9th,  3  Ib.  bran  was  fed  at  milking  time. 
This  was  continued  and  the  milk  returned  to  its  usual  record  before 
pasture  feeding  began. 

The  complete  record  of  the  milk  given  by  cow  No.  16  during  the 
whole  period  of  lactation  shows  that  the  average  composition  of  the  332 
samples  was  solids,  13.3  per  cent;  fat,  3.9  per  cent;  solids  not  fat,  9.4  per 
cent.  The  per  cent  of  solids  was  less  than  12  in  12  samples,  and  only 
one  went  as  low  as  n  per  cent.  It  was  more  than  14.5  in  20  samples 
and  only  once  as  high  as  16  and  19.4  per  cent.  The  per  cent  of  fat  was 
less  than  3  in  12  samples  and  was  less  than  2.4  only  twice.  Eleven 
samples  were  over  5  and  only  one  (9.2)  was  above  6  per  cent  fat. 
The  per  cent  of  solids  not  fat  did  not  go  below  8.5.  It  was  above  10 
per  cent  in  18  samples. 

The  average  composition  of  the  342  samples  of  milk  from  cow  No. 
1 8  was  solids  13.1;  fat,  3.7;  solids  not  fat,  9.4.  Eleven  samples  went 
under  12  per  cent,  the  lowest  one  was  10.2  per  cent.  22  samples  were 
over  14.5  per  cent  solids  and  only  one  (17.8)  above  16.5  per  cent.  One 
sample  contained  2  per  cent  fat,  and  25  were  between  2  and  3  per  cent.  One 
sample  was  above  6.4  per  cent  and  16  between  5  and  6.4  per  cent. 
Eight  samples  contained  less  than  8.5  per  cent,  and  12  went  over  10  per 
cent  solids  not  fat. 

Cows  No.  4  and  5  Holstein.  Each  9  years  old  March,  1892.  The 
record  of  these  two  cows  shows  them  to  be  producers  of  more  but 
thinner  milk  than  the  other  cows.  No.  4  was  a  large  cow  and  varied  in 
weight  from  1258  to  1457  Ib.  in  the  278  days  of  her  milking  period. 
No.  5  varied  less  in  live  weight  during  her  period  of  lactation  than  did 
any  other  cow,  1005  to  1094  Ib.  The  record  shows  that  the  quantity  of 
milk  given  by  both  cows  did  not  decrease  very  much  until  the  last  two 
months.  The  most  milk  given  on  any  one  day  by  No.  4  was  37  Ib.;  No. 


1893-] 


VARIATIONS    IN    MILK. 


'53 


5,  34  lb.  The  daily  average  for  the  year  was  for  No.  4,  2 1.7;  No.  5,  22 
lb.  This  is  a  larger  quantity  per  day  than  any  of  the  other  cows  gave. 
There  were  no  sudden  changes  in  the  weights  of  the  daily  milk  of  No. 
5,  but  No.  4  often  varied  6  to  10  lb.  from  what  she  gave  the  day  previ- 
ous. This  happened  during  pasture  feeding  but  not  before.  The  aver- 
age per  cent  of  solids  in  the  milk  of  No.  4  was  1 1.9  and  of  fat,  3.3.  This 
is  lower  than  the  standard  for  unadulterated  milk  which  some  state  laws 
require.  The  table  shows  for  the  same  cow  that  the  per  cent  of  both 
solids  and  fat  increased  in  the  last  part  of  the  period  of  lactation  and  in 
the  last  two  months  was  over  12  per  cent  solids  and  3.5  per  cent  fat. 
During  the  whole  milking  period  of  278  days  the  per  cent  of  solids  went 
over  13  per  cent  on  29  days,  but  was  over  14.7  only  3  days.  It  was  n 
to  10  per  cent  16  days  and  less  than  10  only  one  day.  The  per  cent  fat 
went  above  4.5  on  25  days,  but  was  over  6  per  cent  only  once.  It  was 
less  than  3  per  cent  on  72  days  but  under  2  per  cent  only  4  days. 

The  per  cent  solids  not  fat  was  over  9  on  24  days  and  reached  10.9 
but  once.  It  was  less  than  8  per  cent  eight  times,  going  once  as  low  as 
7.2  per  cent. 

Cow  No.  4,  HOLSTEIN. — THE  DAILY  AVERAGE  AND  EXTREMES  OBSERVED  DURING 

EACH  MONTH. 

Weighing  and  testing  of  milk  began  Jan.  13,  1892,  and  continued  to  Oct.  16,  1892 — 
278  days. 


Pounds. 

Per  cent. 

Pounds. 

1 

r 

i' 

Milk. 

Solids. 

Butter 
fat. 

Solids 
not  fat. 

n 

Solids. 

Butter 
fat. 

Not  fat. 

r 

W 

W 

M 

W 

5' 

M 

W 

w 

< 

X 

* 

X 

5JT 

x 

^ 

x 

P 

^ 

x 

< 

x 

^ 

x 

r* 

•-I 

r* 

i-t 

^ 

r1 

n 

i"1 

Jan    . 

29.6 

34-7 
27-5 

11.9 

12.6 

10.8 

2.9 

3-6 
2-5 

9 

9-2 
8-3 

2.93 

3-53 

4 

.88 

1.04 

.68 

2.65 

2  84 
2-4 

Feb  .. 

1329 

26.3 

32.7 
18 

ii  .  i 

ii.  8 
10.6 

2.8 

4-1 
2-4 

8-3 

9 

7-2 

2.64 

2-93 

3  36 
1.9 

•75 

1.04 
•43 

2.18 

256 

i-47 

March 

1303 

26.1 

29-5 
20.7 

ii.  8 

12.7 
ii.  i 

3-2 

4-2 

2.8 

8-7 

8.8 

8.2 

2.81 

3.o8 

3-55 
2.31 

-85 

i.  ii 
.62 

2.23 

265 
1.69 

April  . 

1286 

26.5 

33-5 

20.2 

ii.  9 

13.2 

10.4 

3.2 

4-5 

2-7 

8-7 

9-7 

7-8 

2.85 

3-i6 

4 

2-5 

.87 

1.09 
.63 

2.29 

3-32 
i.  59 

May.. 

1379 

29.7 

37 

20.7 

12 

15 
10.6 

3.1 

4-7 

2.2 

8-9 

10.9 

8.2 

3-14 

3-57 

5-°9 
2.46 

•  91 

i-43 
.63 

2.66 

3-57 
1.8 

June.  . 

M48 

24-7 

35.2 
13.2 

ii.  9 

16 

10.  I 

3-4 

6.6 
1.6 

8-5 

9-4 

7-8 

3.22 

2.96 

4.29 
1.36 

•85 

1.6 

•25 

2.  II 

2.99- 
•91 

July  .  . 

1417 

18.6 

27.7 

IO 

12.  I 

14.1 
10.6 

3-6 

5-6 

2-4 

8-5 

9-1 
7-9 

3-45 

2.25 

3-54 

I.  21 

•67 

•  32 

1.58 

2.42 
.81 

Aug  .. 

1370 

14.6 

2O.  2 
9 

12 

14-2 
10.7 

3-7 

5-4 

2.2 

8.3 

8.8 
7-9 

3.63 

1.76 

2.61 

1.2 

54 

.96 
•  31 

1.22 

i-75 

•74 

Sept.  . 

1471 

10.8 

17 

4-7 

I2.4 

14.7 
9-1 

3-8 

5-8 

8.6 

9-7 
7.6 

3.69 

i-34 

2.09 
•64 

•41 

•78 
.23 

•  93 

1-47 

Oct... 

1493 

5-1 

7-7 

13.3 

I7-I 

4 

5-3 

1-7 

9-3 

10.6 
8-4 

4.11 

.68 

I.  08 
.29 

.2 

•  33 
.  i 

.48 

•75 
.26 

For  the  whole  period. 

21.7 

37 

II.  9 

17.1 
9.1 

3-3 

6.6 
1-5 

8.6 

10.9 

7-2 

2.58 

4:*1  •"' 

1.6 
.1 

Totals  j 

6.032 

718.28        198.2 

BULLETIN    NO.    2  J., 


February^ 


Cow  No.  5,  FIoLsrai^. — THE  DAILY  AVKR\G"?  AND  EXTREMES  OBSERVED  DURING 

EACFI  MOMH 

Weighing  and  testing  oE  milk  began  Nov.  30,  1831,  and  continued  to  October  16, 
1892 — 322  days. 


Pounds. 

Per  cent. 

Pounds. 

0 
CJ 

r 

i' 

Milk. 

Solids. 

Butter 
fat. 

Solids 
not  fat. 

0 

i 

Solids. 

Butter 
fat. 

Not  fat. 

BT 

5 

w 

W 

PJ 

PI 

a 

M 

pi 

PI 

.< 

X 

* 

x^ 

.< 

x^ 

5 

x^ 

&> 

* 

x^ 

< 

X 

•* 

x 
H 

Dec  .. 

1048 

25.6 

30 
22.7 

12.2 

i3-5 
11.4 

3  6 

4-3 

2.8 

8.6 

10.7 

8.2 

2.75 

3-13 

3.63 

2.75 

.92 

I  .  II 

.7 

2.21 

2.67 
i.qi 

Jan... 

1035 

30 

33-5 
27-7 

12.7 

14.6 

12 

3-9 

6.2 

3 

8.8 

9-2 
8.4 

2.86 

3.83 

4.42 
2.66 

1.17 

1.87 
•  97 

2.86 

3.01 
1.36 

Feb  .. 

1082 

30.4 

34 
27.2 

12.5 

13-7 

ii.  8 

3-5 

4.8 
3 

9 

9-3 
8.6 

2.9 

3-8 

4-52 
3.52 

i.  08 

i.58 
•94 

2.72 

3-04 
2.44 

March 

1080 

26.9 

30.2 

24-5 

12-5 

13-7 
ii 

3-6 

4-4 

2.6 

8.9 

9-5 

8-5 

2.88 

3-37 

3-73 
2.91 

.98 

1-33 
.69 

2.39 

3-55 
2.19 

April  . 

1049 

23 

29-7 
17.2 

12.6 

16 
11.7 

3-5 

4.5 
2-9 

9-i 

ii  .5 
8-7 

3.01 

2.91 

3-47 
2.27 

.81 

•  99 
.67 

2.  I 

2  6l 

May.. 

1043 

22.5 

29.7 

21 

12.6 

13-7 
ii.  6 

3-4 

4  7 

2.8 

9-2 

9-4 

8-3 

3-39 

2.84 

3.83 
2.49 

•78 

.6 

2.06 

2.7 
1.82 

June.. 

1064 

20.  i 

24.7 

16.2 

12.  1 

13.2 
11.5 

3-5 

4-3 
2.9 

8.6 

9-5 
8.1 

3.o8 

2-45 

3.01 
1.92 

.72 

.89 
.61 

1-73 

2.12 
I.  O2 

July.. 

1067 

20.  i 

23-5 

18.2 

12.  1 

12.7 
ii.  6 

3-6 

3-9 
3-3 

8.5 

9 
7.8 

3.05 

2-45 

2.89 
2.13 

•73 

1.18 
•43 

1.72 

2.05 
1.36 

Aug.. 

1036 

16.5 

20. 
12. 

12.5 

13-6 

12.2 

3-8 

4-8 
3-3 

8.7 

9-3 

7-9 

3-1 

2.07 

1.64 

.64 

.83 
•53 

1-43 

2.27 
I  04 

Sept  .  . 

1082 

ii.  7 

15- 

8. 

13.3 

15.  • 

ii  .8 

4-3 

6.2 

3-1 

9 

9-9 
8-3 

3.54 

1.56 

2 
I  .  14 

•51 

•75 
•34 

1.05 

I.4I 

•79 

Oct... 

1122 

6.7 

9- 
3 

14 

17.8 

12.  I 

4-i 

8 

2.2 

9-9 

ii.  6 

9  2 

4.23 

•94 

•79 

.28 

.48 
•  13 

.66 

•9 
-29 

For  the  whole  period. 

22 

34 
3 

12.4 

17.8 
II 

3-7 

8 

2.2 

8.7 

ii.  6 

7-8 

2.74 

4.52 
•79 

.81 

1.87 
•  13 

Totals 

7,106.4 

885.16 

261  .87 

The  following  table  illustrates  several  of   ihe  sudden  changes  that 
occurred  in  the  milk  of  this  cow,  both  in  amount  and  richness. 
Cow  No   4.     SOME  VARIATIONS  IN  MILK  PRODUCT. 


Milk, 
Ib. 

Per  cent. 

Milk, 
Ib. 

Per  cent. 

Solids 

Fat. 

Solids  not  fat. 

Solids. 

Fat. 

Solids  not  fat. 

May    9 
10 
ii 

12 
13 
M 

27 
24.7 

34 
28.7 

24-5 
3^  

32.7 
29.2 
19.2 
33-5 

ii.  8 

12 

15 
II.  2 

13-7 
II.4 

3 
3 

4.2 

2-5 

4-7 

2.8 

8.8 

9 
10.8 

8.7 
9 
8.6 

June  16 

17 

18 

19 

20 
21 

25 

!6 

15-7 
17.2 
13.2 
17.7 

11.4 

10.  I 

ii.  3 
13-4 
10.3 
12.4 

1.6 
3-3 
5-1 
1-9 
3.8 

8-4 
8-5 
8 

8.3 
8-4 
8.6 

June    i 

2 

3 

4 

12.3 

12.3 
ii.  7 
12.5 

3-6 
3-6 

2'? 
3-6 

8-7 
8.7 
8.8 
8.9 

July   16 

17 
18 

19 

13 
27-5 
23.2 
14.5 

14.1 
11.4 

14 
10.6 

5-6 
3-2 
5-6 
2.4 

8.5 

8.2 

8.4 

8.2 

29 
30 
July     i 

28 
24.2 
25-7 

ii.  6 
16 
ii  9 

2.8 

6.6 
3-4 

8.8 
9-4 
8-5 

Aug.  25 
26 

27 

14.5 
9 
M 

II-5 
13-3 

12 

3 

5-1 
3-2 

8.5 

8.2 

8.8 

VARIATIONS    IN    MILK. 


155 


This  table  shows  four  or  more  distinct  kinds  of  variations.  The 
records  of  May  9th  and  loth  illustrate  the  course  the  milk  had  been 
taking  for  some  time.  May  nth  there  was  an  increase  of  10  Ib.  in  the 
milk  and  a  considerable  increase  in  its  quality;  May  12th  both 
decreased;  May  I3th  the  pounds  of  milk  descended,  the  quality 
ascended;  May  i4th  the  reverse  was  true;  from  June  ist  to  4th  there 
was  a  rising  and  falling  in  the  quantity  of  milk  of  over  14  Ib.,  but  the 
quality  remained  nearly  unchanged;  June  3Oth  the  milk  tested  6.6  per 
cent  fat  and  the  day  before  was  2.8  per  cent,  with  a  change  of  only  4  Ib.  in 
the  quantity.  These  and  the  other  groups  of  tests  given  in  the  above  table 
show  that  with  this  cow  there  was  no  uniform  relation  between  quantity 
and  quality.  A  change  in  one  was  sometimes  accompanied  by  similar 
variation  in  the  other;  and  there  were  times  when  these  deviations  did 
not  coincide.  At  other  times  one  changed  very  noticeably  and  the  other 
did  not.  The  uniformity  in  the  per  cent  of  solids  not  fat,  amidst  all 
these  changes,  is  very  noticeable. 

The  record  of  cow  No.  5  shows  no  such  sudden  changes  as  the 
above.  The  daily  weights  of  milk  varied  only  3  Ib.  and  the  per  cent 
of  solids  and  fat  were  very  uniform  until  the  last  month  of  the  period 
of  lactation,  when  there  was  an  increase  in  quality. 

The  per  cent  of  solids  found  during  the  322  days  was  between  12 
and  14,  except  on  17  days  when  it  went  above  14,  but  only  twice  above 
15.6;  and  on  27  days,  below  12  per  cent  solids,  but  never  below  n  per 
cent.  The  average  per  cent  of  fat  was  3.7,  it  ran  up  to  8  on  one  day  only, 
and  was  above  4.5  per  cent  on  19  days;  2.2  per  cent  was  the  minimum 
which  it  reached  once,  and  only  10  times  in  the  year  was  it  below  3  per 
cent.  The  per  cent  of  solids  not  fat  went  above  9.5  on  14  days  and  be- 
low 8.5  on  28  days,  although  it  was  8.4  on  13  of  these  28  days. 

The  table  on  page  146  gives  the  number  of  samples  of  milk  out  of 
the  total  number  tested  for  cow  No.  i  that  went  above  and  below  cer- 
tain percentages  of  solids,  fat,  and  solids  not  fat.  The  following  table 
shows  the  same  for  the  other  5  cows,  except  that  the  standards  are 
lower. 

It  also  shows  that  by  far  the  greater  number  of  samples  containing 
over  14  per  cent  solids  were  between  14  and  14.5  per  cent.  Those 
under  12  per  cent  solids  were  mostly  between  12  and  11.5  per  cent.  A 
very  large  proportion  of  those  over  4.5  were  between  4.5  and  5  per  cent 
fat,  and  those  under  3  were  nearly  all  included  between  3  and  2.5. 
The  per  cent  solids  not  fat  went  a  few  times  over  10  per  cent,  but 
hardly  ever  under^S  per  cent. 

Different  standards  were  adopted  for  the  milk  of  cow  No.  i,  and  a 
summary  of  the  variations  in  her  milk  is  given  on  page  146. 


156 


BULLETIN    NO.    24, 


\_February  ^ 


NUMBER  OF  DAYS  WHEN    PERCENTAGES   OF  SOLIDS,  FAT,  AND  SOLIDS  NOT  FAT  WERE 

ABOVE  OR  BELOW  CERTAIN  STANDARDS. 

Period  of  lactation— Cow  No.  3,  428  days;  No.  16,  332;  No.  18,  342;  No.  4,  278; 
No.  5,  322. 


Per  cent 
solids. 

Per  cent  solids 
over  14  and 
under   12. 

Per  cent 
fat. 

Per  cent  fat 
over  4.5  and 
under  3. 

Per  cent 
solids 
not  fat. 

Per  cent  solids  not 
fat  over  9.5  and 
under  8.5. 

No.  3 

16 

18 

4 

8 

4 

i 
i 

5 

No.  3 

19 
10 

5 

2 
2 

16 

18 

4 

17 
6 

i 
i 

i 

5 

No.  3 

16 

18 

4 

5 

I4-I4.5 
M-5-I5 
15-16 
16-17 
17-18 
18-19 

Sum  

15 
6 

4 

2 

i 

32 
9 
6 

i 

i 

28 
10 
9 

2 

I 

9 
3 

4 

i 

4-5-5 
5-5-5 
5-5-6 
6-7 
7-8 
8-9 

24 

5 
3 

21 
IO 

6 

9 
5 
4 

i 

9.5-10 
10-10.5 
10.5-11 
n-ii  .5 

12 

81 
8 

2 

86 
15 
3 

IOO 
10 
2 

6 

2 
2 

10 

i 
i 

2 

i 

i 

28 

49 

5° 

J4 

17 

~3» 

32 

~38 

~6 

19 

91 

105 

112 

10 

14 

Per  cent  of 
whole  No.  . 

6-5 

29 
4 
3 

15 

6 
4 

15 
19 

4 

2 

I 

5 
15 

5 

9 
18 

9 

8 

2 
2 

ii 

22 

3 

9 

6 

9 

i 

8.5-8 
8-7-5 

7-5-7 
7 

21 
II 

2 

3i 

2 

33 

8 

2 

3 

25 

7 

i 

4 

26 

4 

12-11.5 
ii  .5-11 
11.5-10 
10-9.5 
9-5-9 

Sum.  .  .  . 

25 

2 

3-2-5 
2.5-2 
2-1-5 
1.5-1 

58 

IO 

4 

37 

10 

26 

15 

27 

18 

12 

25 

72 

IO 

13 

2 

IO 

33 

30 
9 

Per  cent  of 
whole  No.  . 

9 

3 

7 

5 

8 

4 

3 

7 

26 

3 

3 

6 

3 

12 

TOTAL  PRODUCTION  OF  THE  Cows. 

The  following  table  shows  the  difference  between  the  cows  in  total 
production  and  daily  average  during  the  year.  The  figures  for  milk, 
milk  solids,  and  fat  are  found  from  the  daily- weights  and  analyses. 
The  butter  equivalent  of  the  butter  fat  is  found  by  multiplying  the 
pounds  of  fat  by  1.2,  as  recommended  by  Fleischman.  {Landw.  Jahr.^ 
Band  XX.)  The  butter  found  by  the  use  of  this  factor  (1.2)  contains 
83.33  per  cent  fat.  Such  a  calculation  does  not  take  into  account  the 
butter  fat  lost  in  creaming  and  churning  the  milk.  Fleischman  suggests 
that  this  loss  is  about  6  per  cent  of  the  total  product. 

DIFFERENCE  IN  TOTAL  PRODUCTION  AND  DAILY  AVERAGE  COMPOSITION. 


Cow 

No. 

Ave. 
live 
wt.,   Ib. 

Milking 
period, 
days. 

Total  product,  Ib. 

Average  composition  of  milk. 

Milk. 

Solids. 

Fat. 

Butter. 

Solids, 
per  cent. 

Fat, 
per  cent. 

Solids  not  fat, 
per  cent. 

i 

3 
16 
18 
4 
5 

859 

1022 

1108 

1174 

1361 
1054 

307 
428 

332 
342 
278 
322 

5044 
6i93 
3738 
3069 
6032 
7106 

729 

794 
496 
400 
718 

885 

254 
228 
146 

"5 
198 
262 

305 
274 
175 
138 
238 
3i4 

14.4 

12.8 

13-3 
13-1 
11.9 
12.4 

5 
3-7 
3-9 
3-7 
3-3 
3-7 

9-4 

9-2 

9-4 
9-4 

8.6 

8.7 

This  table  shows  that  the  most  milk  was  given  by  No.   5   and  the 
least  by   No.    18.     The   richest  milk   throughout  this  entire   period  of 


VARIATIONS    IN     MILK. 


'57 


lactation  was  given  by  No.  j,  the  poorest  by  No.  4.  The  richest  but 
not  the  most  milk  was  given  in  this  lot  by  the  smallest  and  youngest 
cow.  The  most  and  nearly  the  thinnest,  by  one  of  the  largest  and  oldest 
cows.  These  differences  in  size  and  in  quantity  and  quality  of  the  milk 
are  characteristics  of  the  two  breeds  to  which  these  two  cows  belong; 
hence  in  this  experiment  it  cannot  be  justly  said  that  a  small  or  young 
cow  produces  a  small  amount  of  rich  milk,  or  that  a  large  quantity  of 
thin  milk  is  a  characteristic  of  an  old  or  large  cow.  There  may,  how- 
ever, be  some  relation  between  the  age  or  size  of  the  cow  and  the 
amount  and  richness  of  the  milk  she  produces,  dependent  somewhat  on 
the  food  she  eats  and  assimilates. , 

The  table  also  shows  that  one  cow  was  milked  only  278  days,  and 
another  428  days;  one  weighed  859,  and  another  1361  Ib.  Calculating 
the  record  of  each  cow  for  a  uniform  length  of  time  and  live  weight,  as 
300  days  and  1,000  Ib.,  gives  the  following  results: 

TOTAL  PRODUCTION  COMPARED  WITH  LIVE  WEIGHT. 


Cow 
No. 

i 

16 
18 
4 
5 

Age 
July,  '91, 
years. 

How  many  times 
the  live  weight. 

Pounds  per  1000  Ib.  live  weight. 

For  whole  time. 

For  300  days. 

Per  day. 

Milk. 

5-9 
6 

3-4 

2.6 

4-4 
7-7 

Butter. 

Milk. 

Butter. 

Milk. 

Butter. 

Milk. 

Butter. 

3 
3 

8 

7 
8 
8 

•35 
.26 

.16 

.12 
.18 
•30 

5,870 
6,069 

3.375 
2,614 

4.432 
6,742 

355 
268 

158 
118 

175 
298 

5,739 
4,248 
3,048 

2,292 
4,782 
6,279 

345 

186 
141 
102 
189 
276 

19-13 
14.16 
10.  16 
7.64 

15-94 
20.93 

i-i5 
.62 

•47 
•  34 
•  63 
.92 

The  total  amount  of  milk  and  batter  produced  per  1,000  Ib.  live 
weight  is  calculated  by  multiplying  the  yearly  product  by  i,oooand  then 
dividing  by  the  average  live  weight  of  the  cow.  This  result  divided  by 
the  number  of  days  which  the  cow  was  milked  gives  the  figures  per  day, 
and  multiplying  these  by  300  shows  the  performance  of  each  cow  for 
the  same  live  weight  and  length  of  milking  period.  When  these  cows 
are  compared  on  this  basis  the  figures  for  weight  of  milk  produced, 
place  them  in  the  following  order:  No.  5  first,  No.  i  second,  No.  4 
third,  and  then  No.  3,  16,  and  18.  Comparing  them  as  butter  producers 
per  1,000  Ib.  live  weight  and  300  days  milking  period  puts  No.  i  in  the 
front  rank,  No.  5  second,  and  the  others  in  the  following  order:  No.  4, 
No.  3,  No.  16,  and  No.  18. 

The  difference  in  value  to  the  owner  of  two  cows  like  No.  i  and 
No.  18,  whose  feed  was  the  same,  which  were  milked  the  same  length 
of  time,  and  were  of  uniform  weight,  but  produced  345  and  102  Ib.  but- 
ter respectively,  teaches  a  lesson  in  profit  and  loss  and  shows  what  con- 
trasts can  be  often  found,  probably,  when  cows'  records  are  investigated 
by  weights  and  tests. 

The  maximum  and  minimum  figures  for  the  year  illustrate  a  pos- 
sible error  which  might  be  made  if  it  should  so  happen  that  an  opinion 
of  a  cow's  milk  capacity  was  formed  from  one  test  only,  if  this  test  had 


•58 


BULLETIN     NO.    24. 


February 


been  made  on  the  day  when  either  one  of  the  extreme  results  had  been 
observed.  The  highest  and  lowest  per  cent  of  solids,  fat,  and  solids  not 
fat  on  any  day  during  the  whole  period  of  lactation  are  as  follows: 

EXTREME  VARIATIONS  DURING  PERIOD  OF  LACTATION — PER  CENTS. 


Total  solids. 

Butter  fat. 

Solids  not  fat. 

Extremes. 

Difference 

Extremes. 

Difference. 

Extremes. 

Difference. 

I 

11.9-22.4 

9-5 

2.9-12.3 

9-4 

7.6-11.7 

4.1     . 

3 

10.8-17.8 

7 

2-5-  7-9 

5-4 

7.2-11.3 

4-1 

16 

11-19.4 

8.4 

1.8-  9.2 

7-4 

8.5-10.7 

2.2 

18 

10.2-17.8 

7-6 

2-    8.1 

6.1 

8-1  1 

3 

4 

9  1-17-1 

8 

1.5-  6.6. 

5-i 

7.2-10.9 

3-7 

5 

11-17.8 

6.8 

2.2-   8 

5-8 

7.8-11.6 

3-8 

CALCULATED  TOTAL  PRODUCTION  OF  MILK  AND  BUTTP:R  FAT. 

The  exact  total  production  of  milk  and  butter  fat  in  the  milk  of 
each  cow  was  found  from  the  sum  of  the  numbers  obtained  by  the  daily 
weights  and  tests. 

These  records  furnish  the  data  for  calculating  the  total  production 
of  each  cow  from  weights  and  tests  made  only  one,  two,  three,  or  four 
times  each  month  and  for  comparing  the  yearly  amount  thus  obtained 
with  that  found  from  the  daily  weights  and  tests. 

The  accuracy  of  such  a  computation  depends  a  great  deal  on  the 
cow.  If  the  flow  of  milk  decreases  gradually  from  the  time  the  cow  is 
fresh  until  she  is  dry,  and  there  are  no  sudden  fluctuations  in  the  quality 
from  day  to  day,  her  total  production  for  the  whole  period  of  lactation 
can  be  quite  accurately  calculated  from  comparatively  few  weights  and 
tests.  A  cow  that  does  not  give  milk  of  uniform  quantity  or  quality, 
but  varies  more  or  less  from  day  to  fjay,  requires  a  greater  number  of 
weights  and  tests  of  her  milk  to  make  such  a  calculated  product  agree 
with  that  found  from  daily  weights  and  tests. 

The  records  of  the  six  cows  used  in  this  experiment  show  quite  a 
difference  in  milk  production.  They  differ  not  only  in  the  total  pro- 
duction but  in  the  relative  amount  of  the  total  which  is  produced  in  the 
different  parts  of  the  milking  period.  Some  gave  the  most  milk  when 
they  were  fresh,  but  others  reached  their  maximum  a  few  months  after 
calving.  This  increase  in  quantity  of  milk  was  caused  by  the  feed.  A 
cow  calving  in  January  gave  more  milk  the  following  May  on  pasture 
feed.  This  may  not  be  true  of  all  cow*,  but  it  was  observed  with  one 
of  these.  These  changes  in  the  periods  of  lactation,  and  the  daily  vari- 
ations peculiar  to  each  cow  explain  the  variety  of  deviations  from  the 
total  production  found  when  the  total  production  of  these  cows  was  cal- 
culated from  the  same  number  of  weights  and  tests. 

The  method  used  for  calculating  the  total  production  was  as  fol- 
lows: Multiply  the  average  per  day  of  all  the  test  days  by  the  total 
number  of  days  each  cow  was  milked.  If  a  cow  was  milked  300  days 
and  the  milk  weighed  and  tested  once  every  30  days,  there  were  10  test 


VARIATIONS    IN    MILK. 


159 


days.  The  average  weight  of  milk  and  butter  fat  found  per  day  from 
these  10  test  days  multiplied  by  300  gave  the  calculated  total  product.  If 
the  milk  was  weighed  and  tested  once  in  15,  10  or  7  days  there  were 
20,  30,  or  43  test  days,  from  which  the  daily  average  was  obtained  and 
multiplied  by  300  in  each  case. 

The   following  table  illustrates   the  details  of  a  calculation  of  the 
total  milk  product  of  cow  No.  I,  found  from  tests  made  once  in  30  days. 

METHOD  OF  CALCULATING  MILK  PRODUCT  FROM  TESTS  EVERY  30  DAYS. 
Milking  period  Oct.  6,  1891,  to  August  8,  1892. — 307  days. 


Test  day. 

Pounds, 
milk. 

Per  cent. 

Pounds. 

Solids. 

Fat. 

Solids 

Fat. 

November  4  .... 
December  4  
January  3 

20.5 
18.7 
17.7 

20 

18.2 

19.5 

17.7 

13 

12.2 
3-2 

13-5 
13-8 
14.2 
14.1 
14.4 
14.2 

J4.5 
15.8 

16.3 

18.1 

4-7 
4-6 
4-9 
4-5 
4-7 
4-4 
4-8 
5-5 

6.2 

7.2 

2.76 
2.58 
2.51 
2.82 
2.62 
2.63 

2.57 
2.05 

1-99 
.58 

.96 
.86 
.86 
•  90 
.86 
.81 

.85 
.72 
'.76 
•23 

February  2    .... 

March  3    .... 

April  2  

May  2 

June  i        

July   i  .  . 

July  31  .  , 

Total  

159.7 

23.11 

7-8i 

Average  

15.97 

2.31 

•78 

Average    x    307, 
total  for  year. 

4'903 

709 

240 

The  other  calculations  are  made  in  the  same  way  from  weights  and 
tests  made  once  in  15,  10,  and  7  days. 

The  results  of  an  application  of  this  method  of  calculation  to  the 
records  of  each  cow,  are  given  in  the  following  tables.  They  show  how 
near  to  the  sum  of  all  the  daily  weights  and  tests  computed  weights  and 
tests  can  be  obtained  by  making  weights  and  tests  once  in  30,  15,  10  or  7 
days,  and  what  percentage  of  the  whole  the  computed  weights  represent. 


i6o 


BULLETIN    NO.    24. 


[February, 


TOTAL  PRODUCTION  OF   MILK   AND   BUTTER   FAT   CALCULATED   FROM    WEIGHTS  AND 
TESTS  MADE  I,  2,  3,  AND  4  DAYS  EACH  MONTH. 


Days  between  tests  .... 

Milk. 

Butter  fat. 

30 

15 

IO 

7 

Daily. 
5044 

0 
IOO 

307 
6193 

o 

IOO 

428 

6032 

0 
IOO 

278 

7106 
o 

IOO 

322 
3738 

0 
IOO 

332 

3069 

0 
IOO 

342 

30 

15        10 

7     JDail? 

Cow  No.  i  . 
Total  pounds  

4903 
141 
97-2 

10 

6020 
173 
97-2 
14 

6075 

43 
100.7 

9 

7232 
126 

102 
IO 

3396 
342 
Q0.8 
II 

2770 
299 
90-3 
II 

4970 

74 
98.5 

20 

6076 
117 
98.1 
28 

5900 
132 

97-8 
18 

7181 
75 

101 
21 

3619 
119 
96.8 
22 

3037 
32 
93-4 
22 

5105 

61 

IOI 

30 

6191 

2 
IOO 

42 

5862 
I70 
97-2 
27 

7084 
22 

99-6 
32 

3559 
179 

95-1 
33 

2896 
173 
94-4 
34 

4973 
7i 
98.6 

44 

6121 
72 
98.8 

a" 

6004 

28 
99-5 
40 

6955 
151 
98 
46 

3635 
103 

97-2 
47 

2948 

121 

96.1 

49 

240 
14 
94-5 

10 

224 

98.3 

14 

202 

4 
102 

9 

273 

II 

104 

10 

136 

TO 

93-2 
II 

103 

12 
89.6 

II 

240 
o 

90.9 

20 

223 

5 
97.8 
28 

189 
9 
95-4 
18 

266 

4 
101.5 

21 

!48 
2 
IOI  .4 
22 

H3 
2 
98.2 
22 

256 
2 

100.8 

30 
229 

I 
100.4 

42 

189 
9 
95-4 
27 

264 

2 

100.8 
32 

!52 

6 
104 
33 

109 
6 
94-8 
34 

246 
8 
96.9 
44 

234 
6 

102.6 

61 

189 
9 
95-4 
40 

261 
i 
99-6 
46 

145 

i 

99-3 
47 

109 
6 
94-8 
49 

254 

0 
IOO 

307 
228 

0 
IOO 

428 
198 

0 
IOO 

278 

262 

0 
IOO 

322 

146 

0 
IOO 

332 
115 

o 

IOO 

342 

Varies  from  daily  Ib.  .  . 
Per  cent  of  daily   . 

No.  of  weights  and  tests 
Cow  No.  3. 
Total  pounds 

Varies  from  daily  Ib.  .  . 
Per  cent  of  daily  
No.  of  weights  and  tests 
Cow  No.  4. 
Total  pounds       

Varies  from  daily  Ib.  .  . 

No.  of  weights  and  tests 
Cow  No.  5. 
Total  pounds        

Varies  from  daily  Ib  .  .  . 
Per  cent  of  daily  

No.  of  weights  and  tests 
Cow  No.  id. 
Total  pounds 

Varies  from  daily  Ib.  .  . 
Per  cent  of  daily      .... 

No.  of  weights  and  tests 
Cow  No.  18. 
Total  pounds 

Varies  from  daily  Ib.  .  . 
Per  cent  of  daily. 

No.  of  weights  and  tests 

CALCULATIONS  FOR  TOTAL  WEIGHTS  OF  MILK  AND  BUTTER  FAT  COMPARED  WITH 
DAILY  WEIGHTS  AND  TESTS. 


Cow  

No.    i. 

No.   3. 

No.   4. 

No.  5. 

No.i6. 

No.iS. 

Aver- 
age. 

Deviation 
from  loo. 

Weighing  daily  

Weights  of  milk,  percentages. 

IOO 

98.6 

IOI 

98.5 
97.2 

IOO 

98.8 

IOO 

98.1 

97.2 

IOO 

99.5 
97.2 
97.8 

100.7 

IOO 

98 

99-6 

IOI 
IO2 

IOO 

97.2 

95-1 
96.8 
90.8 

IOO 

96.1 
94-4 
93-4 
90.3 

IOO 

98 
98 
97-6 
96.4 

Once  in  7  days  
Once  in  10  days  
Once  in  15  days  
Once  in  30  days.  .  .  . 

-2 
-2 

-2.4 
-3-6 

Testing   daily  

Weights  of  butter  fat,  percentages. 

IOO 

96.9 
100.8 

96.9 
94-5 

IOO 
IO2.6 

100.4 
97-8 
98.3 

IOO 

95.4 
95.4 

95-4 

IO2 

IOO 

99-6 
100.  8 
101.5 
104 

IOO 

99-3 
104 
98.2 
93-2 

IOO 

94-8 
94-8 
98  2 
89.6 

IOO 

98 
99  4 
98.5 
97 

-2 

-    .6 
-i.5 

Once  in  7  days  

Once  in  10  days  
Once  in  15  days  
Once  in  30  days  

A  summary  of  these  results,  given  in  the  last  table,  shows  what 
percentages  of  total  production  were  found  when  one  to  four  weights 
and  tests  per  month  were  made  of  the  milk  of  these  cows. 

The  summary   tables  show  that  for  calculating  the  total  weight  of 


1893-]  VARIATIONS    IN    MILK.  l6l 

milk  produced  by  all  these  cows,  weighing  the  milk  once  in  seven  days, 
gave  nearest  to  the  total  amount  found  by  daily  weighings.  This  was 
not  true  of  every  cow,  as  the  table  shows  that  with  two  cows  weighing 
the  milk  once  in  10  days  gave  a  total  nearer  that  found  by  the  daily 
weighings.  The  records  of  all  the  cows  show  that  the  difference 
between  the  extreme  percentages  of  the  whole  amount  was  least  by 
weekly  weighings,  and  greatest  when  the  milk  was  weighed  once  in 
30  days. 
Weighing  milk  once  in  7  days.  10  days.  15  days.  30  days. 

Highest  percentage  ..  ..99.5  101  101  102 

Lowest  percentage 96.1  94-4  93-4  9°. 3 

Difference 3.4  6.6  7.6  11.2 

The  table  also,  illustrates  the  variety  of  results  that  are  obtained  by 
applying  this  method  of  calculation  to  different  cows.  No.  16  and  18 
were  very  irregular  in  the  quantity  of  milk  given  from  day  to  day. 
Weighing  their  milk  weekly  gave  only  96  to  97  per  cent  of  the  total 
found  by  daily  weighings,  while  so  small  a  percentage  of  the  whole  was 
only  found  with  the  other  cows  when  their  milk  was  weighed  once  in 
30  days. 

The  results  from  these  six  cows  show  that  calculations  of  the  total 
weight  of  milk  produced  in  one  period  of  lactation  gave  from  96.1  to 
99.5,  average  98,  per  cent  of  the  total  quantity,  when  the  milk  was 
weighed  on  one  day  of  each  week;  101  to  91.4,  average  98,  per  cent, 
when  weighed  once  in  10  days;  101  to  93.4,  average  97.6,  per  cent, 
when  weighed  once  in  15  days;  and  102  to  90.3,  average  96.4,  per  cent, 
when  weighed  once  in  30  days. 

These  same  observations  apply  to  the  calculation  of   the  total   pro- 
duction of  butter  fat. 
Testing  the  milk  once  in         7  days.       10  days.      15  days.     30  days. 

Highest  percentage 102.6          104  101.4          104 

Lowest  percentage 94 .8  94. 8  95-4  89.6 

Difference 7.8  9.2  6  J5-4 

Average  of  the  six  cows.   98  99-4  9^-5  97 

The  average  of  all  the  results  shows  that  weighing  and  testing  the 
milk  every  seventh  day  gave  with  these  six  cows  98  per  cent  of  the 
total  milk,  and  98  per  cent  of  the  total  butter  fat;  98  per  cent  of  the 
milk,  and  99.4  per  cent  of  the  butter  fat,  when  weighed  and  tested  every 
tenth  day;  97.6  per  cent  of  the  milk  and  98.5  per  cent  of  the  butter  fat, 
when  weighed  and  tested  every  fifteenth  day;  96.4  per  cent  of  the  milk 
and  97  per  cent  of  the  butter  fat,  when  weighed  and  tested  every  thir- 
tieth day. 

Does  an  Increase  in  the  Grain  Ration  fed  to  Cows  influence  the 
Richness  of  the  Milk? 

This  question  has  oeen  often  discussed  and  among  the  many  opin- 
ions that  are  expressed  two  at  least  seldom  fail  to  be  given:  First,  taht 


BULLETIN    NO.    24. 


rich  feed  makes  rich  milk,  and  -second,  that  the  milk  may  be  increased 
in  quantity  but  not  in  quality.  These  statements  are  supposed  to  apply 
to  the  milk  of  one  cow  during  one  period  of  lactation.  It  is  obvious  that 
a  certain  amount  of  food  is  necessary  to  keep  a  cow  in  such  condition 
that  she  neither  gains  nor  loses  weight.  This  maintenance  ration  is  a 
variable  quantity  differing  with  cows  of  various  sizes.  It  is  greater  for 
a  cow  weighing  1200  Ib.  than  for  an  Soo-pound  cow.  The  disposal  that 
is  made  of  any  excess  of  food  over  maintenance  probably  depends  on  the 
natural  capacity  of  the  cow.  One  may  convert  the  excess  into  live 
weight;  another  will  show  an  increase  in  milk;  and  it  is  probable  that 
others  gain  neither  in  weight  nor  milk,  the  excess  of  feed  passing  them 
unassimilated. 

Without  further  discussing  the  question  or  expressing  an  opinion, 
the  following  evidence  in  the  shape  of  weights  and  analyses  of  feed  and 
milk  has  been  obtained  from  the  daily  records  of  three  cows,  No.  i,  3, 
and  5.  The  history  of  the  cows  and  of  their  care  and  feed  up  to  Dec. 
25th  has  already  been  given  on  p.  140.  The  changes  in  the  daily  feed 
per  head  of  these  cows  after  Dec.  25th  are  shown  in  the  following  table: 

FEEDING  PERIODS;  MATERIALS  FED,  AND  WEIGHTS  OF  EACH  IN  POUNDS. 


Feeding  Period. 

Corn  and 
cob 
meal. 

Wheat 
bran. 

Oil 
meal 

Timothy 
hay 

Corn 

ensilage 

i 

2 

3 

4 

6 

'8 

Dec.  i-Dec.  25  

6 

8 

10 
12 
12 

pasture 

4 

4 

I 

only. 

2 
2 

4 
5 
6 
6 
6 

10 

6 

12 
12 
12 
12 
22 

20 
20 

"    2  5—  Tan    6 

Jan    6-Feb    2 

Feb  2-   "       17  

"    17-  Apr.     8    . 

Apr.  8-    "     14  .. 

'  '    14—    '  '     ^o 

"    ^o-Sept.    i  .  . 

The  cows  had  access  to  a  straw  stack  when  in  the  yard  during  the 
winter;  but  as  this  was  only  a  short  time  each  day,  and  as  their  grain 
ration  was  heavy,  there  probably  was  little  straw  eaten  by  these  cows 
after  the  first  feeding  period. 

This  course  of  feeding  was  tried  for  the  purpose  of  increasing  the 
richness  of  the  milk  if  such  a  thing  were  possible.  The  table  shows 
that  the  total  grain  feed  per  day  and  head  was  gradually  increased  from 
12  to  24  Ib.  and  the  latter  quantity,  which  was  a  high  feed  for  these 
cows,  was  continued  for  two  months.  The  change  from  a  grain  feed 
of  24  Ib.  to  pasture  feed  and  no  grain  was  made  gradually,  as  the  table 
shows. 

A  chemical  analysis  was  made  of  these  feeding  stuffs  and,  by  the  use 
of  the  digestion  coefficients  published  by  Professor  Jordan,  a  calculation 
shows  that  100  Ib.  of  each  feed  contains  pounds  of  digestible  nutrients 
as  follows: 


1893.] 


VARIATIONS    IN     MILK. 


1 63 


POUNDS  DIGESTIBLE  NUTRIENTS  IN  100  POUNDS  FEED. 


Corn  and 
cob  meal. 

Wheat 
bran. 

Oil 
meal 

Timothy 
hay. 

Ensilage. 

Oat 
straw. 

Organic  matter 

66  7 

M2 

6s  6 

40  8 

24    c 

43  6 

Protein 

12.  Q 

25.6 

Q      I 

I    6 

I    4 

Crude  liber             

2 

3-2 

3  -5 

17 

4    Q 

21    8 

Nitrogen  free  extract.  .  . 
Fat  (ether  extract) 

54-7 

•3 

34-5 
3  6 

27-5 

28.2 

I    c 

17.1 

O   Q 

19.4 

I 

Total  dry  matter  not  the 
digestible  

85-3 

89.7 

87.6 

91 

38.6 

90.4 

An  exact  record  of  the  weight  of  feed  each  cow  had  before  Dec. 
25th  the  writer  was  not  able  to  obtain,  as  the  ensilage  or  straw  was  not 
weighed;  but  assuming  that  the  cows  each  ate  20  Ib.  of  ensilage  daily 
with  10  Ib.  of  hay  and  2  Ib.  of  oil  meal,  the  digestible  nutrients  consumed 
per  day  and  head  are  given  in  the  following  table.  Each  period  in- 
cludes the  time  a  ration  was  fed  without  change. 

The  live  weight  of  cows  No.  3  and  5  was  between  1,000  and  1,100. 
No.  5  did  not  gain  much  during  this  course  of  feeding.  No.  3  increased 
in  weight  from  912  Ib.  to  1097  Ib.  No.  i,  from  800  Ib.  to  900  Ib. 

The  figures  of  the  table  (page  164)  show  the  digestible  nutrients  for 
very  nearly  i,coo  Ib.  live  weight  with  No.  3  and  5,  but  fur  cow  No.  i 
they  would  be  somewhat  larger  as  her  average  weight  was  about  850  Ib. 

The  table  also  gives  the  average  daily  yield  of  milk  and  its  compo- 
sition during  each  feeding  period. 

The  feeding  stuffs  that  are  consumed  by  cows  contain  some  water, 
which  is  sufficient  in  many  to  make  them  juicy,  while  in  others  it  is  only 
perceptible  by  the  loss  in  weight  that  occurs  when  they  are  heated  at 
such  a  temperature  that  none  of  the  vegetable  matter  is  volatilized.  The 
dry  matter  is  the  water  free  substance  of  the  feed.  A  certain  part  of 
the  dry  matter  is  digestible.  The  rest  passes  the  animal  undigested. 
Both  may  contain  the  same  constituents  but  the  digestible  portion  is  of 
greater  interest  to  feeders. 

A  chemical  analysis  of  a  feeding  stuff  shows  approximately  the 
different  groups  of  substances  contained  therein.  Protein  is  the  name 
given  to  that  group  which  contains  nitrogen  in  addition  to  the  carbon, 
hydrogen  and  oxygen.  This  nitrogenous  part  is  the  "  hearty  "  portion 
of  the  feed,  the  "  flesh  former,"  that  group  which  beans  contain  in  a 
large  quantity  and  is  nearly  lacking  in  rice;  or  among  cattle  foods  a 
large  amount  of  protein  is  found  in  cotton  seed  meal  and  very  little  in 
wheat  straw.  The  carbohydrates  include  the  starch,  sugars,  and  cellu- 
lose, and  with  the  fats  make  what  is  often  called  the  "  heat  forming  " 
part  of  the  feed.  The  nutritive  ratio  shows  how  many  times  the  u  heat 
formers"  are  greater  than  the  "flesh  forming"  part  of  the  feed;  or  the 
proportion  of  protein  to  the  sum  of  the  carbohydrates  and  fats.  The 
method  of  calculating  the  potential  energy  and  nutritive  ratio  is  given 
by  the  writer  in  bulletin  No.  9,  p.  319,  of  this  Station.  The  organic 
matter  represents  the  sum  of  the  protein,  carbohydrates  and  fats.  The 
standard  feed  given  in  the  table  represents  what  is  called  a  sufficient  and 


164 


BULLETIN     NO.    24. 


[  February, 


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well  balanced  ration  for  a  milch 
cow--the  nutrients  consumed  per 
day  and  per  1,000  Ib.  live  weight. 

Table  on  this  page  shows 
that  during  period  i  the  feed  of 
these  cows  was  considerably  be- 
low the  standard,  in  everything 
except  fats.  Period  i  the  protein 
was  low.  Period  3  the  feed  was 
very  near  the  standard,  except  the 
fat,  which  was  high.  The  max- 
imum feed  was  reached  in  period 
5,  which  was  51  days  long.  Dur- 
ing this  time  the  feed  eaten  by 
each  cow  daily  was  about  8  Ib., 
or  33  per  cent,  above  the  standard 
in  dry  matter ;  i  Ib.,  or  40  per  cent, 
above  in  protein,  and  .79  Ib.,  or 
158  per  cent,  above  in  fats.  No 
bad  effect  was  noticed  from  the 
6  Ib.  of  oil  meal  fed  daily  in  this, 
or  the  following  two  periods, 
when  the  feed  was  gradually  de- 
creased until  period  7.  The  6  Ib. 
oil  meal  and  22  Ib.  hay  fed  in  pe- 
riod 7  reduced  the  ration  to  very 
near  the  standard,  except  that  it 
was  a  little  low  in  carbohydrates. 

The  nutritive  ratio  was  some- 
what narrowed  from  the  first  pe- 
riod. 

When  the  cows  were  turned 
out  to  pasture  no  grain  was  fed. 
The  grass  in  the  pasture  was  ex- 
cellent feed;  but  the  month  of 
May  was  very  cold  and  rainy. 
This  probably  had  an  influence 
on  the  flow  of  milk. 

The  part  of  the  table  giving 
the  weight  and  composition  of 
the  milk  shows  the  average  per 
day  calculated  from  daily  weights 
and  tests  during  each  period. 
The  milk  of  each  cow  increased 
in  quantity  from  periods  i  to  3. 
This  increase  amounted  to  3  Ib. 


1893-]  VARIATIONS    IX    MILK.  ^5 

per  day  for  No.  i ;  5  Ib.  for  No.  3;  and  6  Ib.  for  No.  5.  The  average 
per  cent  of  solids  was  greater  in  period  2  than  in  i  in  the  milk  of  No. 
i  and  3,  and  but  very  little  different  in  that  of  No.  5.  The  per  cent 
of  fat  increased  in  the  milk  of  No.  i  and  5,  but  decreased  in  that 
of  No.  3  during  period  2.  After  this  time  no  great  change  in  quantity 
or  quality  is  noticeable  in  the  milk  of  any  of  the  cows  until  period  7. 
There  was  a  slight  decrease  in  the  daily  pounds  of  milk  during  the 
in  days,  between  Dec.  25th  and  April  i4th.  This  represents  about 
one-third  of  the  period  of  lactation,  and  it  is  probable  that  there 
would  have  been  a  much  greater  decrease  if  the  feed  had  been  less. 
The  table  shows  that  the  quality  of  the  milk  did  not  increase  by  this 
long  period  of  feeding  which  kept  the  quantity  from  decreasing, 
as  it  would  naturally  have  done,  with  the  progress  of  the  lactation 
period.  There  is  very  little  difference  in  the  per  cent  of  solids  and 
of  fat  in  the  milk  of  the  second  and  sixth  periods,  although  during 
the  intervening  periods  a  ration  very  rich,  in  both  protein  and  fat, 
had  been  fed  for  93  days. 

The  record  of  each  cow  shows  the  same  changes  in  the  milk 
in  periods  7  and  8.  The  nutrients  in  the  daily  feed  were  reduced 
nearly  to  the  standard  in  period  7.  The  daily  milk  yield  of  the 
different  cows  decreased  from  3  to  7  Ib.;  but  the  richness  of  the  milk 
increased  in  every  case.  This  amounted  to  about  one  per  cent  gain 
in  both  solids  and  fat  in  the  milk  of  No.  i,  and  .5  per  cent  to  one 
per  cent  in  that  of  No.  3  and  5.  The  difference  in  feed  was  a  substi- 
tution of  10  Ib.  hay  for  12  Ib.  corn  and  cob  meal.  This  made  a  reduc- 
tion of  1.5  Ib.  dry  matter,  .5  Ib.  protein,  and  .21  Ib.  fats  in  the 
daily  ration  per  head,  and  a  difference  in  the  coarseness  of  the  feed 
represented  by  a  change  from  18  Ib.  grain,  with  12  Ib.  hay  to  6  Ib. 
grain,  with  22  Ib.  hay.  This  ration  was  fed  only  16  days,  and  the 
indications  are  that  if  continued  the  cows  would  have  soon  gone  dry 
in  milk.  When  pasture  feeding  began  there  was  an  increase  in  the 
yield  of  milk  from  each  cow.  The  quality  of  the  milk  decreased 
from  what  it  had  been  during  the  16  days  of  period  7,  which  imme- 
diately preceded;  but  the  per  cent  of  solids  and  of  fat  in  the  milk 
was  about  the  same  in  the  month  of  May  on  pasture  feed,  as  it  had 
been  during  the  winter,  when  the  cows  were  stable  fed  on  a  grain 
ration. 

The  table  gives  the  average  per  cent  of  solids  and  fat  in  the  milk 
produced  during  each  of  the  periods,  which  were  from  6  to  51  days  in 
length.  Such  an  average  does  not  show  the  extremes  that  may  occur 
in  the  amount  and  richness  of  the  daily  milk.  The  inequalities  of 
quantity  and  quality  from  day  to  day  are  covered  up  by  taking  the 
mean  production  for  a  number  of  days.  Twice  in  the  period  of  lacta- 
tion of  these  cows  quite  a  sudden  change  was  made  in  the  flow  of  milk: 
first  when  the  grain  feed  was  increased  during  the  winter  stable  feed- 


1 66  BULLETIN   NO.   24.  [February, 

ing,  and  second  when  the  cows  were  turned  out  to  pasture  in  the 
spring. 

The  four  following  diagrams  on  pp.  167-170  show  these  changes  as 
they  occurred  in  the  weight  and  composition  of  the  milk  from  day  to  day. 
The  first  two  and  the  fourth  plates  give  the  daily  record  of  cows  No.  i, 
3,  and  5  for  a  few  days  before  and  about  30  days  after  the  grain  ration 
was  increased  as  indicated  in  the  table.  The  third  plate  gives  the  record 
of  cow  No.  3  for  a  short  time  before  and  after  pasture  feeding  began. 
Each  diagram  shows  the  record  of  one  cow  for  40  days,  which  are 
designated  by  a  date  every  fifth  day  at  the  top  of  the  diagram.  The 
cows  were  weighed  once  a  week  and  the  live  weight  and  date  of  weigh- 
ing are  indicated  by  the  point  where  the  dotted  and  solid  part  of  the 
44  weight  of  cow"  line  changes.  The  heaviest  broken  line  on  all  the 
plates  indicates  pounds  of  milk,  and  this  is  numbered  on  the  left  hand 
margin  of  the  record  of  cow  No.  i,  but  by  figures  enclosed  by  a  circle 
on  the  other  plates.- 

The  diagram  for  cow  No.  i  shows  the  per  cent  of  solids  between 
the  13  and  14  per  cent  lines,  per  cent  of  fat  between  the  4  and  5  per 
cent  lines,  per  cent  of  solids  not  fat  between  the  9  and  10  per  cent 
lines,  pounds  of  solids  between  the  2  and  3  pound  lines,  pounds  of  fat 
between  the  o  and  i  pound  lines,  and  pounds  of  solids  not  fat  between 
the  i  and  2  pound  lines.  These  percentages  and  pounds  are  indicated 
in  the  other  three  plates  by  the  brackets  and  figures  on  the  two  sides  of 
each  diagram. 

The  grain  ration  was  increased  Dec.  25th  and  the  change  from 
stable  to  pasture  made  April  3oth,  All  the  records  show  that  the 
increase  of  feed  was  accompanied  by  a  considerable  increase  in  the 
pounds  of  milk  produced  and  consequently  in  the  pounds  of  solids, 
fat,  and  solids  not  fat  in  the  milk;  but  with  the  exception  of  one  or 
two  days,  there  were  no  greater  changes  in  the  percentages  of  fat  in 
the  milk  after  the  increase  of  feed  than  before  it  was  made.  There 
was,  however,  a  slight  increase  in  the  per  cent  of  solids  not  fat  in  the 
milk  of  all  the  cows  during  the  latter  part  of  January,  when  the 
increased  grain  ration  had  been  fed  about  a  month. 

All  the  striking  changes  in  the  composition  of  the  milk  produced 
on  any  one  day  are  shown  by  the  diagrams  to  be  due  to  the  per  cent  of 
fat.  This  is  illustrated  by  the  record  of  cow  No.  i  on  Dec.  28th,  Jan. 
5th  and  i5th;  of  No.  5  on  Dec.  i9th,  Jan.  ist  and  i5th;  of  No.  3  on  Jan. 
loth,  23d,  April  i9th,  May  7th,  9th,  and  17111  to  2Oth. 

The  increase  in  the  daily  weight  of  milk  was  greatest  with  cow 
No.  5.  The  diagram  shows  that  she  gave  22^  Ib.  milk  Dec.  23d, 
the  quantity  increased  to  32  Ib  by  Jan.  ist,  a  gain  of  nearly  10 
Ib.  per  day  in  a  little  more  than  a  week. 

No.  i  gave  8  Ib.  more  milk  Jan.  4th  than  Dec.  25th.  No.  3 
increased  from  n  Ib.  Dec.  25th  to  175^  Jan.  9th,  and  when  she  went 
from  stable  to  pasture  feed  she  gained  in  four  days  nearly  6  Ib.  milk 


1893-] 


VARIATIONS    IN    MILK. 


.67 


RECORD  DP  DDW  NO  1 


• -, INDICATED    POUNDS  Otf  MII^K. 

25  50  4  JAN.   9  14  19         24 


1 68 


BULLETIN    NO.    24 


^February, 


RECORD   OP  DDWND  3 

INDICATES   POUNDS    0? 

2ft  2  cTAM.     7  12  17 


'893-] 


VARIATIONS    IN     MILK. 


169 


DAIL.Y  RECORD  OF*  DDW  NO,  3 


16  APR.  2 


•- INDICATED   POTJND0  0^ 

6  11      •        16 


-6 


7° 


BULLETIN    NO.    24. 


^February 


RECORD  DFDQWNQ.  5 


10  DEC.  15 


INDICA1^$ 

20  25          30 


0^  MILK. 

4  JAN.   9 


Saw 


1893-] 


VARIATIONS    IN    MILK. 


per  day.  The  diagrams  show  that  these  changes  in  feed  stimulated  the 
milk  production  of  the  cows  so  that  they  each  gave  from  6  to  10  Ib. 
more  milk  per  day  than  they  had  been  producing;  but  the  quality  of 
the  milk  was  changed  very  little.  The  tables  giving  the  record  of 
each  cow  for  the  whole  milking  period  also  show  that  the  milk  was  of 
the  same  uniform  quality  peculiar  to  the  cow  in  every  month,  except 
the  last  ones  when  the  cows  were  drying  up.  The  average  per  cents  of 
solids  and  of  fat  in  the  milk  produced  each  month  of  the  lactation 
periods  do  not  show  so  great  variations  as  were  observed  in  some  of  the 
different  feeding  periods,  which  were  considerably  less  than  a  month 
in  length. 

When  the  feed  was  decreased  the  yield  of  milk  was  diminished 
and  the  per  cent  of  fat  and  solids  in  the  milk  was  somewhat  increased 
for  a  short  time. 

When  the  pasture  is  abundant  the  amount  of  feed  eaten  is  regu- 
lated by  the  cow,  and  her  milk  product  is  probably  then  controlled  by 
her  natural  capacity.  If  the  quality  of  the  milk  is  not  changed  by  dif- 
ferent amounts  of  grain  feed  from  what  it  is  on  full  pasture  feed,  it 
seems  safe  to  assume  from  this  evidence  that  the  per  cent  of  solids  and 
fat  in  a  cow's  milk  are  not  greatly  influenced  in  one  period  of  lactation 
by  an  increase  of  feed.  The  complete  records  of  all  these  cows  show 
some  peculiarities  in  the  milk  production  that  are  characteristic  of  each 
one  and  others  that  are  common  to  all. 

There  were  a  few  days  during  the  milking  periods  when  the  milk 
was  very  much  richer  or  thinner  than  ordinarily,  but  it  soon  returned  to 
the  quality  peculiar  to  the  cow.  An  inspection  of  the  daily  weights 
and  tests  made  during  the  whole  period  of  lactation  of  each  of  the  cows 
shows  that  four  different  combinations  of  quantity  and  quality  can  be 
found  in  the  milk  of  some  of  the  cows;  more  and  richer,  more  and 
thinner,  less  and  richer,  and  less  and  thinner  milk  than  was  produced  oh 
the  day  before.  Such  changes  were  rare  but  they  show  that  it  is 
entirely  inadmissible  to  assert  that  what  one  cow  has  done  in  this  way 
another  always  can  or  will  do. 

E.  H.  FARRINGTON,  M.S.,  Chemist. 


172  BULLETIN    NO.  24.  [February ^  1893. 


ORGANIZATION. 


BOARD  OF  TRUSTEES  OF  THE  UNIVERSITY  OF  ILLINOIS. 

SAMUEL  A.  BOLLARD,  Springfield,  President. 
JOHN  P.  ALTGELD,  Springfield,  Governor  of  Illinois. 
DAVID  GORE,   Springfield,  President  State  Board  of  Agriculture. 
HENRY  RAAB,  Springfield,  Superintendent  of  Public  Instruction. 
EMORY  COBB,  Kankakee.  GEORGE  R.  SHAWHAN,  Urbana. 

W.  W.  CLEMENS,  Marion.  FRANCIS  M.  McKAY,  Chicago. 

JOHN  H.  BRYANT,  Princeton.  RICHARD  P.  MORGAN,  Dwight. 

ALEXANDER  McLEAN,  Macomb.  NELSON  W.  GRAHAM,  Carbondale. 

BOARD  OF  DIRECTION  OF  THE  EXPERIMENT  STATION. 

GEORGE  E    MORROW,  A.M.,  Champaign,  Professor  of  Agriculture,  President. 

E.  E.  CHESTER,  Champaign,  of  State  Board  of  Agriculture. 

HENRY  M.  DUNLAP,  Savoy,  of  State  Horticultural  Society. 

H.  B.  CURLER,  DeKalb,  of  State  Dairymen's  Association. 

EMORY  COBB,  Kankakee,  Trustee  of  the  University. 

LAFAYETTE  FUNK,   Shirley. 

THOMAS  J.  BURRILL,  Ph.D.,  Urbana,  Professor  of  Botany  and  Horticulture. 

STEPHEN  A.  FORBES,  Ph.D.,  Champaign,  Professor  of  Zoology  and  Entomology 

EDWARD  H.  FARRINGTON,  M.S.,  Champaign,  Chemist  of  Station. 

THE  STATION  STAFF. 

GEORGE  E.  MORROW,  A.M.,  Agriculturist,  President  of  Board  of  Direction. 

WILLIAM  L.  PILLSBURY,  A.M.,  Champaign,  Secretary. 
THOMAS  J.  BURRILL,  Ph.D.,  Horticulturist  and  Botanist. 

EDWARD  H.  FARRINGTON,  M.S.,  Chemist. 
STEPHEN  A.  FORBES,  Ph.D.,  Consulting  Entomologist. 

DONALD  McINTOSH,  V.S.,  Consulting  Veterinarian. 

GEORGE  W.  McCLUER,  B.S.,  Assistant  Horticulturist. 

GEORGE  P.  CLINTON,  B.S  ,  Assistant  Botanist. 

E.  K.  NELSON,  Assistant  Chemist. 
FRANK  D    GARDNER,  B.S.,  Assistant  Agriculturist. 


UNIVERSITY  OF  ILLINOIS-URBANA 


